Preheat oven to 350º F and lightly grease a 9×13-inch baking dish with non-stick spray.
In a large bowl, combine chicken, black beans, corn, 1 cup Mexican blend cheese, diced tomatoes and green chiles, cream of chicken soup, sour cream, and taco seasoning. Mix together until completely incorporated.
Spread half of your lightly crushed Doritos chips into the baking dish, then pour the chicken mixture over the top and spread it into an even layer.
Bake in preheated oven for 20 minutes.
Remove from oven and top with remaining Doritos and cheese. Return to oven and bake for another 5-7 minutes, or until cheese is melted and bubbly.
Cheesy Chicken Casserole with a Crunchy Doritos Topping
