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 bottom of the prepared dish. Drizzle olive oil evenly over the tops. Bake for 20 minutes until tater tots begin to turn golden and develop a crisp exterior.
03 - Remove the dish from the oven. Spread pizza sauce evenly over the partially cooked tater tots using the back of a spoon. Sprinkle dried oregano, basil, and garlic powder over the sauce layer.
04 - Sprinkle half of the mozzarella and cheddar cheese over the sauce. Arrange pepperoni, black olives, bell pepper, and red onion across the cheese. Top with remaining mozzarella, cheddar, and Parmesan cheese.
05 - Return the casserole to the oven and bake for an additional 20 minutes until the cheese is fully melted, bubbly, and beginning to brown on edges.
06 - Allow the casserole to rest for 5 minutes before serving. This helps the cheese set slightly for cleaner portions.