Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
In a large frying pan over medium heat, brown the ground beef, breaking it up as it cooks until no longer pink. Drain any excess grease.
Add the diced onion and chopped bell pepper to the pan. Cook for about 5 minutes until softened. Add the garlic in the last minute and cook until fragrant.

Stir in the tomato sauce, Worcestershire sauce, mustard, brown sugar, salt, and pepper. Let it simmer for 5 minutes to develop the flavours.
Spread the beef mixture evenly in your prepared baking dish. Sprinkle 1 cup of cheese over the top.
Arrange the frozen tater tots in a single layer over the cheese, covering as evenly as possible.
Bake for 25-30 minutes until the tater tots are golden brown and crispy.
Sprinkle the remaining 1 cup of cheese over the tater tots and bake for another 5 minutes until the cheese is melted and bubbly.
Let rest for a few minutes before serving. Enjoy!