Preheat oven to 350. Mix 2c shredded chicken, 2c shredded cheese, 1 can of cream of chicken soup, 1/2c milk, 1/2c sour cream, can of drained rotel, & 1/2 pack taco seasoning. Grease casserole dish. Crush 1/2 bag doritos and place in bottom, top with mixture, crush a few doritos on top. Bake for 30 minutes. Garnish with lettuce and diced tomatoes.