Preheat your oven to 375°F (190°C).
In a large skillet, brown the ground beef over medium heat, breaking it apart with a spatula until it's fully cooked.
Add the diced onions and green bell peppers to the skillet. Sauté for 5-7 minutes until the vegetables are softened.
Stir in the Sloppy Joe sauce, garlic powder, salt, and pepper. Cook for an additional 3-4 minutes to combine the flavors.
Spread the meat and vegetable mixture in an even layer at the bottom of a greased 9x13-inch baking dish.
Top the meat mixture evenly with the frozen tater tots in a single layer.
Sprinkle the shredded cheddar cheese generously over the tater tots.
Bake in the preheated oven for 30-35 minutes, or until the tater tots are golden brown and the cheese is bubbly.
Allow the casserole to cool for 5-10 minutes before serving.