In a large skillet over medium heat, cook the ground beef until browned. Drain excess fat.
Add the chopped onion, bell pepper, and minced garlic to the skillet. Sauté until the vegetables are softened, about 5 minutes.
Stir in the black beans, corn, diced tomatoes, cream of mushroom soup, chili powder, cumin, salt, and pepper. Mix well and let simmer for 5 minutes.
In a slow cooker, layer half of the beef mixture on the bottom. Sprinkle 1 cup of shredded cheddar cheese over the beef mixture.
Add a layer of frozen tater tots on top of the cheese. Repeat the layers with the remaining beef mixture, another cup of cheese, and finish with the remaining tater tots.
Cover and cook on low for 4-6 hours or on high for 2-3 hours, until the tater tots are golden and crispy.
In the last 15 minutes of cooking, sprinkle the remaining cheddar cheese on top and cover until melted.