01 - Preheat oven to 400°F. Grease a 9x13-inch baking dish with cooking spray or a light coating of oil.
02 - Arrange frozen tater tots in a single layer across the prepared baking dish. Drizzle olive oil evenly over the tops. Bake for 20 minutes until lightly golden and beginning to crisp.
03 - Remove dish from oven. Spread pizza sauce evenly over the partially cooked tots. Sprinkle dried oregano, basil, and garlic powder across the sauce layer.
04 - Sprinkle half of the mozzarella and cheddar cheese over the sauce. Distribute pepperoni, black olives, bell pepper, and red onion evenly across the cheese. Top with remaining mozzarella, cheddar, and Parmesan cheese.
05 - Return casserole to oven and bake for 20 additional minutes, or until cheese is fully melted, bubbly, and lightly golden brown on top.
06 - Let casserole rest for 5 minutes before serving to allow cheese to set and make cutting easier.