Preheat oven to 375 degrees. Brown ground meat; Drain. Add taco seasoning and cook as taco packet is directed.
In a large bowl add the cream of chicken soup, fiesta cheese, corn, beans, Rotel, about half of the grated cheese. Mix together. Open the bag of Doritos a little bit then crunch the Doritos into small pieces and pour them into the bowl. Mix thoroughly.
Spray Casserole dish with Pam. Slowly put the mixture into the casserole dish. Even out. Sprinkle the rest of the cheese on top. Cover with foil for the first 30 minutes. Uncover for last 15 minutes. Let stand 15 minutes before serving.ENJOY!