Preheat oven to 375°F and lightly grease a 9x13-inch baking dish.
In a large skillet over medium-high heat, cook ground beef with diced onion until beef is browned and crumbled into fine pieces, about 8-10 minutes. Drain excess grease thoroughly.
Add garlic, salt, and pepper to the beef and cook for 1 minute until fragrant.
Stir in both cans of soup, frozen vegetables, and 1 cup of shredded cheese. Mix until well combined.
Spread the beef mixture evenly in the prepared baking dish.
Arrange tater tots in a single layer on top of the beef mixture, covering completely.
Bake for 35-40 minutes until tater tots are golden brown and crispy.
Sprinkle remaining 1 cup of cheese over the tater tots and bake for an additional 5 minutes until cheese is melted.