Step 1: Preheat oven to 350º F and light grease a 9×13-inch baking dish with non-stick spray.
Step 2: 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.
Step 3: 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.
Step 4: Bake in preheated oven for 20 minutes.
Step 5: 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.
Step 6: Remove from oven and serve hot, garnished with cilantro, if desired.