Packed with chicken, beans, tomatoes, and tortillas, this chicken tortilla casserole is one of my favorites, no matter the season. The best part is that once this casserole is baked, it can be customized by anyone in your family. Top it with guacamole, sour cream, spicy peppers, or anything your heart desires, and it will be a delicious weeknight meal.
In a large skillet, heat 2 tbsp of neutral oil over medium heat. Add the onion, bell pepper, and salt. Sauté until the vegetables are translucent and beginning to brown, 4-6 minutes. Add the chili powder and cumin. Stir the spices into the hot oil to bloom the spices for 30 seconds.
Add the diced tomatoes and tomato sauce and stir to incorporate. Place the chicken breasts over the tomatoes and bring the mixture to a low simmer. Once at a simmer, cover and cook until the chicken breasts reach 160°F, 12 to 15 minutes. After the chicken has cooked, remove the breasts from the pot and set them aside to cool. Add the kidney beans to the tomatoes and stir to combine.
When the chicken is cool enough to handle, shred the breasts into small pieces.
Preheat the oven to 350°F.
Remove the tomatoes and beans from the heat. Grease a 9x13 baking dish and spread ½ cup of the tomato mixture over the bottom of the baking dish. Add the shredded chicken to the mixture and combine. Lay two tortillas over the thin layer of tomatoes. The tortillas will overlap. Add ⅓ of the tomato mixture and spread evenly. Sprinkle with 1 cup of cheese and ½ of the chopped cilantro. Repeat these layers two more times ending with the final two cups of cheese on top of the casserole.
Bake in the preheated 350°F oven until the cheese is beginning to brown and the casserole is bubbling throughout, 45-55 minutes. Once baked, remove from the oven and cool for 15 minutes before serving.