This keto creamy chicken fajita casserole has all the flavor of sizzling fajitas, baked into one cheesy dish. Shredded chicken, sliced bell peppers, and warm fajita spices get mixed with cream cheese and sour cream, then topped with cheddar. It comes out bubbly, golden, and very filling.

It is also a great way to use up leftover or rotisserie chicken. You stir everything together in one bowl, spread it in a dish, and bake it for about 30 minutes. The recipe serves four and stays low in carbs, so it fits a keto or low-carb plan without feeling like diet food.

Why This Casserole Works

Cream cheese and sour cream make a thick, tangy base that coats every bite of chicken. You do not need to make a sauce on the stove. As it bakes, the cheese melts into the mixture and holds it all together.

The spice mix does the heavy lifting. Chili powder, cumin, garlic powder, and onion powder give you that classic fajita taste without a packet of seasoning, which often has added sugar or starch. The bell peppers add sweetness, color, and a little crunch.

Because the chicken is already cooked, the oven only needs to heat everything through and brown the cheese. That keeps the bake time short and the chicken moist.

Ingredients and Easy Swaps

• Cooked chicken: Rotisserie chicken is the easiest choice. Leftover grilled chicken or poached chicken breasts also work. Shred it into bite-size pieces.
• Cream cheese: Let it soften on the counter for 30 minutes so it mixes in smoothly. Full-fat gives the best texture.
• Sour cream: Plain Greek yogurt works, though it is a bit tangier.
• Cheddar cheese: Monterey Jack or a Mexican blend are good swaps. Pepper Jack adds heat.
• Bell peppers: A mix of red and yellow looks best. Green peppers work too and have a slightly bitter edge.
• Spices: Chili powder, cumin, garlic powder, onion powder, salt, and pepper. Add a pinch of cayenne if you like it spicy.
• Cilantro: Use sliced green onions if cilantro tastes like soap to you.

How to Make It at a Glance

1. Heat the oven to 350°F and lightly grease a baking dish.
2. In a large bowl, mix the chicken, cream cheese, sour cream, half the cheddar, bell peppers, and all the spices.
3. Spread the mixture evenly in the baking dish.
4. Top with the rest of the cheddar.
5. Bake for 25 to 30 minutes, until the cheese is bubbly and golden.
6. Let it cool a few minutes, then top with cilantro and serve.

Common Mistakes to Avoid

Using cold cream cheese. Cold cream cheese leaves white lumps in the casserole. Soften it first, or microwave it for 15 to 20 seconds.

Leaving the chicken in big chunks. Small shreds mix better and give you chicken in every bite. Two forks work well for this.

Cutting the peppers too thick. The peppers only bake for about 30 minutes. Thin slices turn tender, while thick strips stay firm. You can also sauté them for a few minutes first if you like them soft.

Skipping the rest. Straight from the oven, the filling is loose. Five minutes on the counter helps it set so it scoops cleanly.

Variations

• Spicy: Add a pinch of cayenne, a diced jalapeño, or use pepper Jack cheese.
• Onion and pepper: Add half a sliced onion with the bell peppers for a more classic fajita mix. It adds a few carbs.
• Green chile: Stir in a small can of diced green chiles.
• Bacon: Fold in four slices of crumbled cooked bacon.
• Not keto: Serve it with warm flour tortillas or spoon it over rice.

What to Serve With It

On its own, this casserole is rich, so a fresh side helps. Here are some low-carb ideas:

• Avocado slices or a scoop of guacamole
• A simple green salad with lime vinaigrette
• Cauliflower rice with a squeeze of lime
• Roasted zucchini or green beans
• Low-carb tortillas for scooping

Salsa and an extra dollop of sour cream on top are never a bad idea.

Make Ahead, Storage, and Reheating

Make ahead: Mix and assemble the casserole up to one day ahead. Cover it and keep it in the fridge. Add 5 to 10 minutes to the bake time since it goes in cold.

Storage: Keep leftovers in a covered container in the fridge for up to four days.

Reheating: Warm single portions in the microwave for 1 to 2 minutes, or reheat the dish covered in a 350°F oven for 15 to 20 minutes. Reheat chicken leftovers to 165°F.

Freezing: You can freeze it for up to two months. The texture of the cream cheese gets a little grainy, but the flavor stays good. Thaw it in the fridge overnight before reheating.

Frequently Asked Questions

Can I use raw chicken?
This recipe is built for cooked chicken. If you start with raw chicken, cook it first by baking, poaching, or sautéing it until it reaches 165°F, then shred it.

What size baking dish should I use?
An 8×8 inch or similar 2-quart dish works well for four servings. A larger dish gives a thinner layer that may bake a few minutes faster.

Is this casserole spicy?
It is mild. The chili powder and cumin add warmth more than heat. Add cayenne or jalapeños if you want a kick.

How many carbs are in it?
The main carbs come from the bell peppers, sour cream, and cream cheese. It stays low in carbs per serving, but check your own brands if you track closely.