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, even 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 baked tater tots. Sprinkle dried oregano, basil, and garlic powder over the sauce.
04 - Top with half of the shredded mozzarella and cheddar cheese. Distribute pepperoni slices, black olives, diced bell pepper, and red onion across the surface. Finish with remaining mozzarella, cheddar, and grated Parmesan.
05 - Return casserole to oven and bake for 20 minutes until cheese is fully melted, bubbly, and beginning to turn golden brown.
06 - Allow casserole to rest for 5 minutes before serving to set the cheese layers and make cutting easier.