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