Preheat the oven to 375°F (190°C). Grease a 9x13-inch baking dish and set aside.
In a large skillet over medium heat, cook the ground beef, chopped bell pepper, and onion until the beef is browned and the vegetables are soft. Drain any excess grease.
Stir in the condensed tomato soup, mixing well to coat the beef and vegetables.
Spread the beef mixture evenly in the prepared baking dish. Layer half of the pepperoni slices over the meat.
Sprinkle 1 cup of shredded mozzarella cheese over the mixture, then arrange the tater tots in a single layer on top.
Bake uncovered for 30 minutes. Remove from the oven, sprinkle the remaining 1 cup of mozzarella cheese over the tots, and add the remaining pepperoni slices.
Return to the oven and bake for an additional 15-20 minutes, or until the cheese is melted and the tater tots are golden brown.
Let cool for a few minutes before serving. Enjoy!