This streamlined Tex-Mex casserole transforms classic fajita flavors—seasoned chicken, sautéed peppers and onions, and melted cheese—into a convenient one-dish meal by combining everything with rice, creamy soup base, and zesty tomatoes with chilies. The recipe eliminates traditional fajita preparation steps like marinating, grilling, and individual assembly, instead layering all components in a 9×13-inch baking dish where they meld into a cohesive, satisfying dinner. With its beginner-friendly technique, efficient use of convenience products like instant rice and pre-shredded rotisserie chicken, and guaranteed crowd-pleasing Tex-Mex flavors, this casserole represents the perfect solution for busy weeknights when you want bold, restaurant-inspired taste without the complexity, time investment, or multiple pans that traditional fajitas require.

Why You’ll Love This Recipe

• Complete Meal Simplicity – This all-in-one casserole contains protein, starch, vegetables, and dairy in a single dish, eliminating the need for side dishes while minimizing both preparation and cleanup.
• Rotisserie Chicken Shortcut – Using pre-cooked shredded chicken (rotisserie or leftover) cuts preparation time dramatically while maintaining excellent flavor and tender texture throughout the casserole.
• Instant Rice Efficiency – Uncooked instant rice added directly to the casserole absorbs liquid during baking, eliminating the step of cooking rice separately and reducing active preparation time.
• Beginner-Friendly Assembly – This straightforward mix-and-bake method requires no special techniques, making it accessible to novice cooks while delivering results that taste far more complicated than the simple preparation suggests.
• Fajita Flavor Without the Fuss – All the beloved Tex-Mex seasonings, peppers, onions, and cheese you expect from fajitas, transformed into convenient casserole format without marinating, grilling, or individual tortilla assembly.
• Make-Ahead Capability – The casserole can be fully assembled hours ahead and refrigerated until baking time, making dinner preparation stress-free during chaotic afternoons or when entertaining.

Ingredients You’ll Need

For the Main Components

• 4 cups shredded cooked chicken breast – Provides the protein foundation; approximately 600g or about one large rotisserie chicken yields this amount, with meat removed from bones and shredded into bite-sized pieces.
• 2 cups uncooked instant white rice – Creates the starchy base that absorbs liquid and binds the casserole; approximately 370g, with instant rice cooking during baking without pre-preparation required.
• 1 can cream of chicken soup – Forms the creamy binding agent; standard 10.75 oz or 298g can, which creates cohesive texture and adds savory chicken flavor throughout.
• 1 cup sour cream – Adds tangy richness and additional creaminess; approximately 240g, with full-fat sour cream providing best flavor and texture without separating during baking.
• 1 cup frozen diced onion and bell pepper blend – Contributes the essential fajita vegetables; approximately 140g, with frozen blend eliminating chopping while providing authentic flavor and color.
• 1 can diced tomatoes with chilies, undrained – Delivers Tex-Mex flavor through tomatoes and mild green chilies; standard 10 oz or 284g can (like Rotel), with the liquid providing essential moisture.
• 360 ml chicken broth – Adds savory liquid that cooks the rice; approximately 1.5 cups, with low-sodium broth recommended to control salt levels as fajita seasoning contains sodium.
• 1 packet fajita seasoning – Provides the signature blend of spices including cumin, chili powder, garlic, onion, and paprika; standard 1 oz or 32g packet delivers authentic Tex-Mex flavor without measuring individual spices.
• 1 bag shredded Mexican-style cheese blend – Creates the melted, gooey topping; approximately 8 oz or 227g, with Mexican blend typically containing cheddar, Monterey Jack, and possibly queso quesadilla for optimal melting.

Step-by-Step Instructions

Prepare the Baking Dish and Oven

Preheat your oven to 175°C (350°F), positioning the rack in the center for even heat distribution. Lightly coat a 9×13-inch (23×33 cm) baking dish with non-stick cooking spray, ensuring complete coverage including corners and sides to prevent sticking and facilitate serving.

Combine All Casserole Components

In a large mixing bowl, combine the shredded cooked chicken, uncooked instant rice, cream of chicken soup, sour cream, frozen diced onion and bell pepper blend, undrained diced tomatoes with chilies (including all liquid from the can), chicken broth, fajita seasoning packet, and half of the shredded Mexican cheese blend (reserve the other half for topping). Using a large spoon or spatula, stir the mixture thoroughly for 1-2 minutes until all ingredients are evenly distributed and incorporated, ensuring the rice is dispersed throughout rather than settling at the bottom, and the seasonings coat everything uniformly.

Transfer and Smooth

Pour the prepared mixture into the greased 9×13-inch baking dish, using a spatula to spread it evenly across the entire surface and into corners. Smooth the top with the spatula to create a relatively level surface that will bake evenly, ensuring no significant mounds or valleys remain that would cause uneven cooking.

Cover and Bake

Cover the baking dish tightly with aluminum foil, crimping the edges to seal and trap steam that will cook the rice. Place the covered dish in the preheated 350°F oven and bake for 35 minutes. During this covered baking period, the rice will absorb the liquid, the chicken will heat through, and all flavors will meld together without the top drying out or browning prematurely.

Add Cheese Topping

After 35 minutes, carefully remove the baking dish from the oven (use oven mitts as it will be very hot). Remove the aluminum foil, being cautious of the steam that will escape. Sprinkle the reserved half of the shredded Mexican cheese blend evenly over the entire top surface of the casserole, distributing it to the edges for complete coverage. Return the uncovered dish to the oven and bake for an additional 10 minutes, until the cheese is completely melted, bubbly, and just beginning to develop golden spots on the surface.

Rest Before Serving

Remove the casserole from the oven and let it rest at room temperature for 5 minutes before cutting and serving. This crucial resting period allows the rice to finish absorbing any remaining liquid, the structure to set slightly from residual heat, and makes cleaner, more attractive portions possible when scooping. The brief cooling also brings the temperature down from scalding to comfortably hot for eating.

Serve and Enjoy

Using a large spoon or spatula, scoop generous portions of the casserole onto plates, ensuring each serving contains chicken, rice, vegetables, sauce, and melted cheese. The texture should be creamy and cohesive rather than soupy or dry, with tender rice and moist chicken throughout.

Recipe Notes & Tips

• Chicken Options – Rotisserie chicken provides the quickest option requiring only shredding; alternatively, use leftover cooked chicken, poach chicken breasts specifically for this recipe, or even use canned chicken in emergencies.
• Instant Rice Critical – This recipe specifically requires instant/minute rice that cooks quickly; regular long-grain rice won’t cook properly in the 45-minute baking time and will remain hard and crunchy.
• Liquid Balance – The casserole should appear quite liquid when assembled; this is correct, as the rice will absorb most liquid during baking—if it appears dry before baking, add 1/4 cup additional broth.
• Foil Sealing – Ensure the aluminum foil creates a tight seal around the dish edges; this traps steam essential for cooking the rice properly and preventing the top from drying out before the center cooks.
• Make-Ahead Assembly – Prepare the entire casserole up to 24 hours ahead, cover, and refrigerate; add 10-15 minutes to the covered baking time if baking directly from cold.
• Spice Level Adjustment – For milder flavor, use regular diced tomatoes instead of those with chilies; for more heat, add diced jalapeños or use hot-style Rotel tomatoes.

Nutritional Information

• Prep Time: 15 minutes (shredding chicken if needed, measuring ingredients, mixing)
• Cooking Time: 45 minutes (35 minutes covered, 10 minutes uncovered)
• Overall Time: 60 minutes (plus 5 minutes resting)
• Servings: 8 servings (approximately 1.5 cups per serving from a 9×13-inch dish)
• Calories: Approximately 375 per serving (estimated based on standard ingredients)

Perfect Pairings

• Fresh Pico de Gallo or Salsa – Serve with fresh tomato salsa or pico de gallo on the side for bright acidity and fresh vegetable crunch that contrasts the creamy casserole.
• Tortilla Chips – Accompany with crispy tortilla chips for scooping, adding satisfying crunch and making the meal feel more complete and festive.
• Simple Mexican Rice or Refried Beans – While the casserole contains rice, some may want additional sides; black beans, refried beans, or cilantro-lime rice complement nicely.
• Shredded Lettuce and Diced Tomatoes – Offer fresh shredded lettuce, diced tomatoes, sliced avocado, or guacamole for topping individual portions with cool, fresh elements.

Ideal Occasions

• Busy Weeknight Dinners – The straightforward preparation and hands-off baking make this perfect for hectic evenings when you need filling meals without constant attention.
• Potluck Contributions – The 9×13-inch pan travels well and serves 8 people, making this ideal for church suppers, office gatherings, or neighborhood potlucks.
• Casual Entertaining – Serve at informal gatherings, game-day parties, or family celebrations where Tex-Mex flavors feel appropriately festive without formality.
• Meal Prep Sundays – Prepare multiple casseroles on weekends for reheating throughout the week, or freeze for future emergency dinners when time or energy for cooking is limited.

Storage & Serving Tips

• Refrigerator Storage – Store leftover casserole covered in the baking dish or transferred to an airtight container for 3-4 days; the flavors meld and intensify during storage.
• Reheating Instructions – Reheat individual portions in the microwave for 2-3 minutes until steaming hot, or warm the entire casserole covered with foil at 350°F for 20-25 minutes.
• Freezer Storage – Cool completely, wrap tightly in plastic wrap followed by aluminum foil, and freeze for up to 3 months; thaw overnight in the refrigerator before reheating.
• Serving Suggestions – Top individual servings with sour cream, sliced green onions, fresh cilantro, diced avocado, or pickled jalapeños for customized flavor and presentation.

Creative Variations to Try

• Beef Fajita Version – Replace chicken with seasoned cooked ground beef or thinly sliced sautéed steak for different protein while maintaining the fajita flavor profile.
• Vegetarian Adaptation – Omit chicken and add black beans, pinto beans, and extra vegetables like corn, zucchini, or additional bell peppers for plant-based version.
• Spicy Upgrade – Add diced jalapeños, use pepper jack cheese instead of Mexican blend, incorporate chipotle peppers in adobo sauce, or use hot fajita seasoning for heat lovers.
• Southwest Corn Addition – Stir in 1 cup of frozen corn kernels for added sweetness, color, and textural variety that complements the Tex-Mex flavors.

Troubleshooting Common Issues

• Crunchy, Undercooked Rice – Insufficient liquid or not covering tightly causes hard rice; ensure proper liquid measurements and tight foil seal, and continue baking in 5-minute increments if needed.
• Watery, Soupy Consistency – Using regular rice instead of instant or adding too much liquid creates excess moisture; use only instant rice and measure liquids carefully.
• Dry, Tough Texture – Overbaking or insufficient liquid causes dryness; don’t exceed 45 minutes total baking time and ensure foil seals properly during covered baking to trap moisture.
• Bland Overall Flavor – Insufficient seasoning or old fajita seasoning creates flat taste; ensure full packet of fresh fajita seasoning and taste the mixture before baking, adding salt if needed.

Why This Recipe Works

Fajita Chicken Casserole Bake succeeds through the efficient transformation of traditional fajita components into a streamlined, cohesive baked dish that requires minimal technique while delivering authentic flavor. The cream of chicken soup and sour cream create a creamy binding agent that keeps the chicken moist and creates sauce throughout the casserole, preventing dryness that could occur from oven baking. The instant rice cooks directly in the casserole by absorbing the liquid from chicken broth, undrained tomatoes, and moisture from other ingredients during the covered baking period—this technique eliminates a separate cooking step while ensuring the rice becomes tender and flavorful. The fajita seasoning packet provides the signature blend of cumin, chili powder, garlic, onion, and paprika that would require measuring multiple individual spices, simplifying preparation while delivering consistent, authentic Tex-Mex flavor. The frozen pepper and onion blend contributes the essential fajita vegetables without requiring fresh produce chopping, while their frozen state prevents excess moisture release that could make the casserole watery. The diced tomatoes with chilies (Rotel-style) add brightness, acidity, and mild heat that balance the richness of cream and cheese. Covering with foil during initial baking traps steam that cooks the rice while preventing the top from drying or burning before the center finishes. The final uncovered baking with cheese creates the golden, bubbly topping that signals completion and provides textural contrast. At approximately 375 calories per serving, this represents a moderate, complete meal where calories derive from protein (chicken, cheese), carbohydrates (rice, tomatoes), and fats (sour cream, soup, cheese)—a balanced profile that provides sustained energy and lasting satiation.

Final Thoughts

Fajita Chicken Casserole Bake represents the practical evolution of restaurant-style dishes into home-cooking convenience, maintaining the bold flavors people love while adapting format and technique for busy modern lifestyles. This recipe appeals particularly to families managing multiple schedules, novice cooks seeking reliable success without complicated skills, or anyone craving Tex-Mex satisfaction without the hands-on preparation that traditional fajitas demand. The casserole format naturally encourages communal eating and simplified serving—no individual tortilla assembly, no passing multiple toppings, just straightforward scooping onto plates—making dinner feel less like work and more like gathering together. The efficient use of convenience products (rotisserie chicken, instant rice, frozen vegetables, cream soup, seasoning packet) demonstrates how modern shortcuts can create genuinely delicious results rather than inferior compromises, particularly when thoughtfully combined. The beginner-friendly designation accurately reflects the straightforward technique, while the satisfying results prove that simple methods can yield impressive flavor when quality ingredients and proper ratios combine correctly. While the 375-calorie estimate per serving represents hearty nourishment, the complete meal nature means no additional components are required beyond optional fresh toppings, and the portions naturally satisfy without excessive consumption. For those seeking lighter versions, consider using reduced-fat soup and sour cream, increasing vegetables, reducing cheese, or using brown instant rice if available; though these modifications will alter the creamy comfort food character that defines this dish’s appeal. Ultimately, this recipe deserves permanent status in weeknight dinner rotations as proof that satisfying, flavorful, family-approved meals needn’t require culinary expertise, extensive time, or complicated preparation—sometimes the best cooking comes from understanding what people enjoy, combining those elements efficiently, and serving with the confidence that empty plates and contented diners are always the truest measures of success.