Preheat the oven to 375°F (190°C).
In a skillet over medium heat, cook the ground beef and onion until the beef is browned and the onion is translucent. Drain any excess grease.
Stir in the cream of mushroom soup and season with salt and pepper to taste.
Spread the beef mixture evenly into a greased 9x13-inch baking dish.
Sprinkle the shredded cheddar cheese over the beef mixture.
Arrange the frozen tater tots in a single layer over the cheese.
Bake for 30-35 minutes or until the tater tots are golden brown and crispy.
Let cool for a few minutes before serving.