Preheat the oven to 350°F (175°C).

In a large skillet over medium heat, brown the ground beef until fully cooked, breaking it up as it cooks. Add the diced onion and cook until softened, about 3-4 minutes. Season with salt and pepper.

In a large bowl, combine the cream of mushroom and cream of chicken soups. Stir well to blend.

Add the cooked beef and onions to the soup mixture and mix until evenly coated.

In a greased baking dish (9x13 inches), spread the meat and soup mixture evenly across the bottom.

Layer the frozen tater tots evenly over the top.

Bake in the preheated oven for 25 minutes.

Remove from the oven and sprinkle the shredded cheese over the tater tots. Return to the oven and bake for an additional 15 minutes, or until the cheese is melted and bubbly, and the tater tots are golden brown.

Let cool slightly before serving.