King Ranch chicken casserole layers tortillas, chicken, and a spicy cream sauce for a beloved Texas family dish. This protein-packed, freezer-friendly casserole is rich, flavorful, and always a hit.
Preheat the oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.
In a large skillet over medium heat, melt the butter. Sauté the chopped onion and green bell pepper for 4-5 minutes until softened.
Sprinkle flour over the vegetables and stir constantly for 1 minute, then whisk in the chicken broth gradually. Cook and stir until thickened, about 2 minutes.
Reduce the heat to low, then add sour cream, chili powder, cumin, salt, pepper, and drained diced tomatoes with green chilies. Stir until fully combined and creamy; remove from heat.
Spread 4 tortillas across the bottom of the dish, tearing to fit if needed. Layer with half the shredded chicken, half the sauce, and half the cheeses. Repeat layers (tortillas, chicken, sauce, cheese) one more time.
Cover loosely with foil and bake for 25 minutes. Uncover, bake an additional 10-15 minutes until the cheese is bubbly and golden brown on top. Let rest 10 minutes before slicing for best texture.