Preheat oven to 350 degrees F. Grease a 9x13-inch baking dish with butter or non-stick cooking spray.
In a large skillet over medium-high heat, add olive oil and heat until warm. Add chicken and sautto warm up the meat and then add the chile powder. Stir with spatula until chili powder is distributed evenly over all the chicken meat. Remove chicken meat from skillet and set aside.
Turn heat down to medium, add butter and heat until just melted. Add onions and bell peppers and sautfor a few minutes until vegetables are softened and onions appear translucent.
Next add nacho cheese soup, cream of mushroom soup, cream of chicken soup, and the diced tomatoes with liquid and green chiles. Stir together to combine and heat until mixture just begins to boil, stirring occasionally. Remove from heat and add the chicken mixture and stir together to combine; set aside.
In the prepared baking dish, add a small scoop of the creamed chicken mixture and spread the sauce all over the bottom of the pan. Next cover the entire bottom of the pan with corn tortillas. Cover the corn tortillas with a layer of the creamy chicken mixture, spreading across the entire pan. Sprinkle shredded cheese over the entire layer of chicken mixture until fully covered.
Repeat the layering steps one more time ending with shredded cheese on top.
Place the prepared casserole on a baking sheet and place in the middle over rack. Bake approximately 35 to 40 minutes until casserole is bubbly.
Remove from oven to let cool for 10 to 15 minutes before serving. Garnish with your favorite toppings and serve with tortilla chips and enjoy!
If you would like to make this casserole in advance, cover and refrigerate for up to 24 hours. When ready to bake, remove from refrigerator and bring to room temperature or add 10 to 15 minutes to baking time.
Freezing Instructions: Can freeze unbaked casserole with 2 layers of aluminum foil for up to 1 month. Thaw overnight in refrigerator and bake as directed.
Serves 8 to 10.
* Can substitute 3 to 4 chicken breasts, cooked, deboned, and shredded.
** Can substitute with green bell peppers.
*** See Bechamel Sauce - Basic White Sauce to make your own cream of chicken and mushroom sauce.
**** If unable to find Ro-Tel brand, substitute 1 (14.5-ounce) can of diced tomatoes and 1 (7-ounce) can of diced green chiles.
King Ranch Chicken Casserole Recipe: https://whatscookingamerica.net/poultry/king-ranch-chickencasserole.htm