Chicken Fajita Casserole is a fun and easy way to enjoy all the great flavors of fajitas in one comforting dish. You’ll find tender chicken, colorful bell peppers, and onions all baked together with melty cheese and fajita spices that give it a nice kick. It’s a great twist on the classic fajita night, but in a cozy, casserole form that’s perfect for feeding a family or a crowd.
I love making this casserole because it’s simple to throw together, and it always feels like a little celebration at the dinner table. Plus, it’s a great way to use up leftover veggies or chicken if you have some on hand. I usually add a little extra cheese on top before baking so it gets all bubbly and golden brown–such a crowd-pleaser!
My favorite way to serve this dish is with a side of warm tortillas and some fresh guacamole or sour cream. You can mix and match toppings like salsa or cilantro to make it your own. It’s a meal that feels bright and fresh but still filling and satisfying, which makes it perfect for any weeknight dinner or weekend get-together.
Key Ingredients & Substitutions
Chicken: I like using boneless skinless chicken breasts for a lean option, but thighs work well too and stay juicy. If you prefer, rotisserie chicken can be a time-saver.
Bell Peppers: Try to get a mix of colors for a bright, fresh look and varied flavors. Red, yellow, and green peppers are classic, but orange peppers also work great.
Cheese: Cheddar and Monterey Jack are my favorites here because they melt nicely and have a mild flavor. If you want a sharper taste, swap cheddar for pepper jack or a Mexican cheese blend.
Spices: Chili powder, smoked paprika, and cumin give that signature fajita flavor. If you don’t have smoked paprika, regular paprika is fine—it just won’t have that smoky kick.
How Do You Get the Veggies Just Right in a Fajita Casserole?
The peppers and onions should be cooked to stay tender but still have a little crunch. Here’s how I do it:
- Cook the chicken first until browned and nearly cooked through to build flavor.
- Add the sliced peppers and onions and cook them for just 4-5 minutes until slightly softened, but not mushy.
- This way, they keep a fresh texture and bright color under the cheese topping.
- If you like softer veggies, cook them a minute or two longer before baking.
Equipment You’ll Need
- Large ovenproof skillet or cast iron pan – I prefer this because it goes from stovetop to oven easily and heats evenly.
- Knife and cutting board – for slicing chicken, peppers, and onions, making prep quick and simple.
- Measuring spoons and cups – to add your spices and cheese perfectly.
- Oven mitts – for safely handling the hot skillet when baking and serving.
Flavor Variations & Add-Ins
- Swap chicken for cooked shrimp or beef strips for a different protein twist.
- Add sliced jalapeños or a dash of hot sauce for extra heat.
- Mix in corn or black beans for more texture and flavor.
- Use pepper jack or queso fresco instead of cheddar and Monterey Jack for a richer, cheesier taste.
Chicken Fajita Casserole
Ingredients You’ll Need:
For the Chicken and Vegetables:
- 2 lbs boneless skinless chicken breasts or thighs, thinly sliced
- 1 red bell pepper, thinly sliced
- 1 yellow bell pepper, thinly sliced
- 1 green bell pepper, thinly sliced (optional)
- 1 large onion, thinly sliced
- 2 tbsp olive oil
For the Seasoning:
- 2 tsp chili powder
- 1 tsp smoked paprika
- 1 tsp ground cumin
- ½ tsp garlic powder
- ½ tsp onion powder
- ¼ tsp cayenne pepper (optional for heat)
- Salt and black pepper, to taste
For the Cheese and Garnish:
- 1 cup shredded cheddar cheese
- 1 cup shredded Monterey Jack cheese
- Fresh cilantro, chopped for garnish
How Much Time Will You Need?
This recipe takes about 15 minutes to prepare and cook on the stovetop, plus 10 minutes to bake in the oven. In total, plan for around 25 minutes to enjoy a warm, cheesy Chicken Fajita Casserole at your table.
Step-by-Step Instructions:
1. Preheat the Oven and Cook Chicken:
Set your oven to 375°F (190°C). Heat olive oil in a large ovenproof skillet or cast iron pan over medium-high heat. Add the sliced chicken, then sprinkle the chili powder, smoked paprika, cumin, garlic powder, onion powder, cayenne pepper (if using), salt, and black pepper over it. Stir occasionally as the chicken cooks and browns, about 6 to 8 minutes.
2. Add Bell Peppers and Onion:
Stir in the sliced red, yellow, and green bell peppers, along with the onion. Cook everything together for 4 to 5 minutes until the veggies are just tender but still retain some crunch.
3. Sprinkle with Cheese and Bake:
Evenly distribute the cheddar and Monterey Jack cheeses over the chicken and vegetables. Transfer the skillet to your preheated oven and bake for about 10 minutes, or until the cheese is melted, bubbly, and starting to turn golden.
4. Garnish and Serve:
Remove the casserole from the oven, sprinkle with chopped fresh cilantro for a burst of freshness, and serve hot. This dish is great on its own or enjoyed with warm tortillas, sour cream, guacamole, or salsa.
Can I Use Frozen Chicken for This Casserole?
Yes, you can use frozen chicken, but make sure to fully thaw it first. Thaw it in the fridge overnight or place the sealed chicken in cold water for quicker thawing. Pat dry before cooking to avoid excess moisture.
Can I Prep the Casserole Ahead of Time?
Absolutely! You can prepare the chicken and veggies and assemble the casserole in the skillet, then refrigerate it for up to 24 hours before baking. When ready, bake as directed, adding a few extra minutes if going straight from the fridge.
How Should I Store Leftovers?
Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave until warmed through. Adding a splash of water or broth before reheating can help keep it moist.
What Can I Serve With Chicken Fajita Casserole?
This casserole pairs wonderfully with warm tortillas, rice, or a fresh salad. Toppings like sour cream, guacamole, or salsa add extra flavor and balance the smoky spices.
