Cover the bottom and sides of a greased 12-inch cast iron skillet or oven-safe pan with tater tot crowns.
Bake at 425° for 15 minutes.
While the tater tots are baking, brown the ground beef and drain the fat. Add water, diced tomatoes, taco seasoning, and minced onion. Stir and cook for 3-4 minutes, until thickened.
Remove the tater tots from the oven and flatten them with a spatula.
Top with one cup of shredded cheese and the taco meat mixture. Drizzle with taco sauce. Finish it off with another cup of shredded cheese.
Bake for an additional 10-15 minutes at 425°.
Remove from the oven and top with shredded lettuce, crushed Doritos or tortilla chips, diced tomatoes, and shredded cheese.