Chicken Fajita Casserole

This Chicken Fajita Casserole takes all your favorite fajita flavors and turns them into one easy family dinner. Juicy chicken, bell peppers, and onions are baked in a creamy sauce with plenty of Mexican spices and cheese. 

Load it up with fresh toppings like pico de gallo, guacamole, or a dollop of sour cream - just like you would with regular fajitas! It's a fun twist on taco night that brings everyone to the table ready to dig in.

I'm a big fan of easy casseroles. I love making this Chicken Fajita Casserole because it's a delicious and easy twist on traditional fajitas. If you have small children, you’ll love that there's no mess from filling individual tortillas at the table. 

Plus, the cream cheese sauce makes it extra special - it gets all melty and blends with the Mexican spices to create something the whole family will love. 

My favorite part is setting up a toppings bar and letting everyone customize their plate. I always put out bowls of fresh pico de gallo, sliced avocado, and sour cream. My family likes to add extra cheese on top, while my husband piles his high with pickled jalapeños for some heat.

We usually serve this with Spanish Rice on the side - it's perfect for soaking up all that creamy sauce. Sometimes I'll warm up some refried beans too, and throw some tortillas in the oven for anyone who wants to make a regular fajita. It's such an easy way to turn an ordinary weeknight into a treat.

You can also make this casserole your own by switching up the ingredients. If chicken thighs are what I have on hand, I’ll use those, or I'll grab a rotisserie chicken when I'm short on time. Another easy fajita dish is this Shrimp Fajitas Skillet.

Ingredient Notes

See the printable recipe card below for all ingredients, specific measurements, and complete instructions.

• Chicken: Boneless, skinless chicken breasts work perfectly here. Cut them into evenly sized pieces so they cook at the same rate. You can also use chicken thighs if that’s what you have. 
• Bell peppers: The mix of red, green, and yellow peppers adds great color and flavor. Feel free to use whatever colors you have on hand.
• Cream cheese and sour cream: These create the creamy sauce that makes this dish special. Make sure your cream cheese is softened so it mixes smoothly. You can swap the sour cream for Greek yogurt if you prefer.
• Taco seasoning: Store-bought taco seasoning works great and keeps things simple. 
• Diced tomatoes with green chiles: This adds moisture and a bit of bite to the dish. We love using the Rotel brand. 
• Monterey Jack and Sharp Cheddar: This cheese combo gives you the perfect mix of flavor and melt. Feel free to use any Mexican cheese blend you like.
• Avocado oil: Great for high-heat cooking when browning the chicken. You can substitute with vegetable or olive oil if needed.
• Garlic: Fresh minced garlic adds so much more flavor than garlic powder. 

How To Make Chicken Fajita Casserole

Start by preheating your oven to 400°F and greasing a 9x13 inch baking dish. While the oven heats up, cut your chicken into bite-sized pieces - try to keep them similar in size so they cook evenly.

Heat avocado oil in a large skillet over medium-high heat. Add your chicken pieces and cook them until they're nicely browned, about 5-7 minutes. 

Now, add your colorful mix of sliced bell peppers and onions to the skillet. Cook everything together, stirring occasionally, until the vegetables become tender and slightly caramelized, around 8 minutes. Toss in the minced garlic and cook for another 30-45 seconds until it smells fragrant.

Next, stir in the drained diced tomatoes with green chiles. In a separate bowl, mix your creamy ingredients - blend together the softened cream cheese, sour cream, taco seasoning, oregano, and salt until they're well combined. Add this cream cheese mixture to your skillet and stir until everything is evenly coated and heated through.

Transfer your chicken and vegetable mixture to the prepared baking dish. Top it with an even layer of both kinds of shredded cheese. Bake for 15-20 minutes, until the cheese is completely melted and starting to turn golden brown on top.

Let the casserole rest for about 5 minutes after it comes out of the oven - this helps the sauce set up a bit. If you're using cilantro, sprinkle it on top just before serving. Your chicken fajita casserole is ready to enjoy!

Make-Ahead, Storing and Freezing

Make Ahead: You can assemble the entire casserole up to the point of baking and keep it covered in the refrigerator for up to 24 hours. When you're ready to serve, just add the shredded cheese on top and bake as directed. You might need to add a few extra minutes to the baking time since it'll be starting cold.

Store: Keep your chicken fajita casserole in an airtight container in the refrigerator for up to 3 days. Reheat individual portions in the microwave until warmed through, or heat the whole casserole in the oven at 350°F, covered with foil, until hot.

Freeze: This casserole freezes well! Assemble everything except the cheese topping, wrap it tightly with foil, and freeze for up to 3 months. When you're ready to cook it, thaw it overnight in the refrigerator. Add the cheese topping and bake as directed, adding a few extra minutes to ensure it's heated through.

Substitutions and Variations

• Use rotisserie chicken. For a super quick version, skip the chicken cooking step and use shredded rotisserie chicken instead. Just sauté the vegetables, then mix in your shredded chicken.
• Switch up the protein. This casserole works great with sliced steak or shrimp instead of chicken. Just adjust cooking times accordingly - shrimp only needs 2-3 minutes to cook through.
• Make it spicier. Add some diced jalapeños to the pepper mix, use pepper jack cheese on top, or mix some cayenne pepper into your seasoning blend.

Recipe Tips

• Drain the canned tomatoes well to prevent your casserole from becoming watery.
• Use freshly shredded cheese rather than pre-shredded if possible. It melts more smoothly and creates a better texture on top.
• Let the casserole rest for 5-10 minutes after baking. This helps the sauce thicken up and makes serving easier.
• If you notice the cheese browning too quickly while baking, loosely cover the dish with foil to prevent burning while the casserole heats through.

What can I use if I can't find diced tomatoes with green chiles?

Regular diced tomatoes work fine - just add a small can of diced green chiles separately.

If you need more easy casseroles for busy weeknight dinners, try this Big Mac Tater Tot Casserole, Chicken Broccoli Rice Casserole, and Ham and Cheese Casserole.

This Chicken Fajita Casserole combines everything you love about fajitas into one easy dish. The tender chicken and peppers in that creamy, cheesy sauce make it so satisfying, and everyone can add their favorite toppings just like with regular fajitas!