1. Brown the beef, onions, and pepper in a large, deep skillet over medium heat, breaking it up as it cooks. When the meat is cooked through, drain and return to pan.
2. Stir in the seasoning packet, tomato sauce, and the can of diced tomatoes (do not drain). Cook over medium heat for 10 minutes, stirring occasionally. While chili is cooking, preheat oven to 425 degrees.
3. Stir in the sour cream and remove from the heat.
4. Pour chili into a 13x9 baking dish and top with the cheddar cheese.
5. Place tater tots in an even layer over the chili and sprinkle with chopped cilantro.
6. Bake for 25 minutes or until tots are as crisp as you'd like. Remove from oven and serve immediately.