Preheat oven to 350. Boil chicken until cooked through. Let cool, then shred apart in bite size pieces. Layer 9x13” baking dish with ½ of the Doritos. Crush the other half of Doritos and set aside. In a medium bowl, mix cream of chicken, cream of mushroom, cream of celery, chicken and Rotel together. Pour over Doritos. Sprinkle crushed Doritos on top of the chicken mixture. Top with shredded cheese and bake 30 minutes, until cheese completely melts.