How to Make It
Preheat oven to 350°F. Heat vegetable oil in a large skillet over medium-high. Add onion and cook until softened and translucent, about 6 minutes. Add garlic and cook for another minute. Add beef and break apart with a spoon; cook until brown. Add taco seasoning and stir to incorporate.
Add black beans, pinto beans, tomatoes, green chiles, sour cream, 1/2 cup cheddar cheese, and hot sauce, stir into meat mixture and allow to cook until the liquid thickens, about 5 minutes. Stir in frozen corn and transfer mixture to a greased 9- x- 13-inch baking dish.
Line surface of casserole with a single layer of frozen tater tots. Cover dish with aluminum foil and bake for 30 minutes. Remove aluminum foil, sprinkle remaining 1/4 cup cheddar cheese over tater tots, and return to oven for 20 more minutes. Allow to cool slightly before serving.