Preheat oven to 375°F. Spray 13x9-inch glass baking dish with cooking spray; set aside. Combine biscuits, chicken, undrained tomatoes, celery, pepper sauce and 1/2 cup cheese in large bowl.
Place mixture in baking dish; bake 20 minutes. Top with remaining 1 cup cheese; bake 5 minutes more or until cheese melts and biscuits are golden brown. Drizzle with ranch dressing just before serving, if desired.