Preheat your oven to 400°F (200°C). Lightly grease a 9x13 inch baking dish.
In a large skillet or Dutch oven, heat the olive oil over medium-high heat. Add the diced onion and cook for 4-5 minutes, until softened.
Add the ground beef to the skillet. Break it apart with a spoon and cook until nicely browned. Drain off any excess grease.
Stir in the minced garlic and cook for another minute until fragrant.
Reduce the heat to low. Add the sour cream, milk, Worcestershire sauce, onion powder, garlic powder, paprika, salt, and pepper. Stir until a cohesive, creamy sauce forms.
Stir in the frozen corn and 2 cups of the shredded cheddar cheese. Continue stirring until the cheese is just beginning to melt and everything is well combined.
Pour the beef mixture into the prepared baking dish and spread it into an even layer.
Arrange the frozen tater tots in a single, even layer over the top of the beef mixture, covering the entire surface.
Place the casserole in the preheated oven and bake for 30 minutes, until the tots are starting to look golden brown.
Carefully remove the dish from the oven and sprinkle the remaining 1 cup of shredded cheddar cheese evenly over the tater tots.
Return the casserole to the oven and bake for another 10-15 minutes, until the cheese is fully melted and bubbly and the tots are a deep golden brown.
Let the casserole rest for at least 5-10 minutes before serving to allow the filling to set. Garnish with fresh parsley or chives if desired.