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