Meanwhile, in a large skillet, cook beef over medium heat until no longer pink, breaking into crumbles, 6-8 minutes; drain. Stir in taco seasoning and water. Bring to a boil; cook and stir until thickened, about 2 minutes.
To serve, top Tater Tots with beef mixture, cheese, lettuce and, if desired, olives. Serve with taco sauce and sour cream.