Preheat the Oven: Preheat your oven to 375°F (190°C).

Cook the Ground Beef: In a large skillet, warm the olive oil over medium heat. Add the chopped onions and sauté for 3 to 4 minutes until they become translucent. Introduce the ground beef to the skillet and cook until it’s nicely browned, using a spatula to crumble it. Season with salt and pepper according to your preference, and drain any excess fat.

Mix the Filling: In a large mixing bowl, combine the browned ground beef, cream of mushroom soup, sour cream, and drained corn. Stir well to combine.

Assemble the Casserole: In a greased 9x13-inch baking dish, spread the beef mixture evenly. Evenly distribute half of the shredded cheddar cheese over the beef mixture.

Add the Tater Tots: Arrange the frozen tater tots in a single layer over the casserole filling.

Bake: Place the skillet in the preheated oven and bake for 25 to 30 minutes, or until the tater tots are crispy and golden. Once done, take it out and add the remaining cheddar cheese on top. Return it to the oven for an additional 5 minutes, or until the cheese is melted and bubbly.

Serve: Allow the casserole to cool for a few moments before serving. Enjoy this deliciously cheesy, crispy, and comforting dish with your favorite sides!