Combine the tater tots, diced ham, 1 cup cheddar cheese and mozzarella into 9x13 baking dish.
In a large bowl, whisk together the eggs, milk, sour cream, seasonings and hot sauce. Pour the egg mixture over the tater tot mixture in pan.
Bake in preheated oven for 45 minutes. Top with remaining 1/2 cup of cheddar cheese and return to oven for 5-10 minutes more.
(This casserole can be assembled and refrigerated the day before.)