Preheat the oven to 375°F.
In a large skillet over medium heat, brown the ground beef with the diced onion until the meat is cooked through and the onion is translucent. Drain any excess fat.
Stir in the cream of mushroom soup, frozen mixed vegetables, garlic powder, onion powder, salt, and pepper. Mix well and cook for an additional 2-3 minutes until heated through.
Spread the beef mixture evenly in a 9x13-inch baking dish.
Top with shredded cheddar cheese, then layer the frozen tater tots on top of the cheese in a single, even layer.
Bake in the preheated oven for 30-35 minutes, or until the tater tots are golden brown and crispy.
Let cool for 5 minutes before serving.