Preheat your oven to 350°F (175°C).
In a skillet, brown the ground beef over medium heat.
Add diced onion and cook until softened.
Stir in the frozen mixed vegetables and heat through.
Mix in the cream of mushroom soup and season with salt and pepper.
Spread the beef mixture evenly in a greased 9x13-inch baking dish.
Sprinkle shredded cheddar cheese over the beef mixture.
Arrange the frozen tater tots on top in a single layer.
Bake in the preheated oven for 30 minutes until the tater tots are golden brown.
Remove from the oven and let it cool for a few minutes before serving.