Preheat oven to 375°F (190°C).
In a large skillet over medium-high heat, brown the ground beef and diced onions until meat is fully cooked; drain excess grease.
Stir in the taco seasoning, condensed soup, milk, frozen corn, and 1 cup of shredded cheddar cheese.
Spread the beef mixture into an even layer in a 9x13 inch baking dish.
Arrange the frozen tater tots in a single layer over the beef mixture and season with black pepper.
Bake for 20 minutes.
Sprinkle the remaining 1 cup of cheddar cheese over the tater tots and bake for an additional 10 minutes until the cheese is melted and tots are crispy.