This creamy, cheesy pasta bake is filled with seasoned chicken, sweet bell peppers, salsa, and plenty of melted cheese.

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There are certain dinners that everyone is happy to see on the table, and this Fiesta Chicken Pasta Bake is one of them. It is creamy, cheesy, full of flavor, and incredibly simple to make.

I have been making some version of this casserole for years. Cooked pasta gets tossed with seasoned shredded chicken, sautéed peppers and onions, salsa, sour cream, and plenty of cheese. The salsa and sour cream come together to make the easiest creamy sauce without having to cook anything separately.

This is also a great recipe when you already have cooked chicken in the refrigerator. In the video, I used chicken breasts that I cooked in the Instant Pot with chicken stock and taco seasoning, but rotisserie chicken or any leftover shredded chicken will work just as well.

You can assemble the entire casserole earlier in the day and refrigerate it until you are ready to bake. That makes it especially helpful on busy evenings when you want a comforting homemade dinner without doing all the work right before everyone is ready to eat.

Main Ingredients & Swaps

Shredded chicken: Any cooked and shredded chicken will work. Use leftover roasted chicken, Instant Pot chicken, or meat pulled from a rotisserie chicken.
Penne pasta: Penne holds onto the creamy salsa sauce nicely, but another short pasta such as rigatoni, ziti, or rotini would also work.
Bell peppers: I like using yellow and orange peppers because they are sweet and mild. Red bell peppers are also a good choice.
Onion and garlic: These give the chicken and vegetable mixture a flavorful base.
Taco seasoning: You can make the simple seasoning blend included with the recipe or use your favorite prepared taco seasoning. If the prepared blend contains salt, reduce the additional salt slightly.
Salsa: Use a salsa that you already know you enjoy because its flavor comes through in the finished casserole. Homemade salsa makes this especially delicious.
Sour cream: This mixes with the salsa to create a creamy sauce that coats the pasta without needing a separate roux.
Cheese: A combination of sharp white cheddar and a good melting cheese gives you the best flavor and texture. Monterey Jack or Colby Jack both melt beautifully.

How I Make It

If I am using the homemade taco seasoning, I begin by mixing together the chili powder, cumin, paprika, garlic powder, onion powder, oregano, and black pepper.

Next, I heat the avocado oil in a large skillet and sauté the diced onion and bell peppers for about five minutes. Once the vegetables have softened, I add the garlic and cook it for another minute.

I stir in the cooked shredded chicken, taco seasoning, and salt. The chicken only needs about three to four minutes in the skillet since it is already cooked. I am simply warming it through and giving it time to absorb the seasoning.

While the chicken mixture cooks, I boil the penne until it is just al dente. I generously salt the pasta water with kosher salt because this is the main opportunity to season the pasta itself. Most of that salt stays behind when the pasta is drained.

I transfer the drained pasta to a large 9 by 13 inch casserole dish. Then I add the sour cream and salsa directly to the pasta and stir until everything is evenly coated.

The seasoned chicken and vegetables go in next. I mix everything together, spread it evenly in the dish, and cover the top with shredded cheese.

The casserole bakes at 350°F or 175°C for about 25 minutes. It is ready when the sauce is bubbling around the edges and the cheese is melted and lightly golden.

Tips and Storage

Cook the pasta only until al dente. It will continue cooking slightly in the oven, so you do not want it to become too soft while boiling.
For the creamiest casserole, make sure the pasta is thoroughly coated with the salsa and sour cream before adding the chicken mixture.
If you assemble the casserole ahead of time, cover it and refrigerate it until you are ready to bake. Let the cold dish sit at room temperature while the oven preheats, then add a few extra minutes to the baking time if needed.
Store leftovers in an airtight container in the refrigerator for up to four days. Reheat individual portions in the microwave or cover the casserole and warm it in the oven. A small spoonful of salsa or sour cream can help loosen the sauce after refrigeration.

Watch my YouTube video below to see this Fiesta Chicken Pasta Bake come together in my real life kitchen, complete with homemade salsa and the usual dinner time chaos.

This is the kind of dependable casserole that deserves a spot in the regular dinner rotation. It uses simple ingredients, makes plenty of food, and gives you that creamy, cheesy comfort everyone is hoping for at the end of the day.