Grease a 9x13 pan and place the tater tots in a single layer. Sprinkle 1 cup of cheese evenly over the tots.
2
Chop the bacon into 1" pieces. Cook bacon pieces over medium heat in a 10-inch skillet until crisp, then transfer to a paper towel-lined plate. Leave 2 tablespoons of bacon fat in the skillet.
3
Sauté onions in the skillet until softened, then add bell peppers and combine. Layer the onion and bell pepper mixture over the tater tots, followed by ⅔ of the cooked bacon.
4
Whisk eggs, milk, garlic powder, salt, and pepper in a bowl. Pour over the tater tots. Cover the pan tightly with foil and refrigerate overnight.
5
Preheat the oven to 350°F. Bake the covered casserole for 40 minutes.
6
Remove the foil, top the casserole with the remaining cheese and bacon, and increase the oven temperature to 425°F. Bake for an additional 15-20 minutes or until set and cheese is browned. Rest 5 minutes before serving.