01 - Preheat oven to 375°F. Lightly grease a 9x13 inch baking dish with cooking spray or butter.
02 - In a large skillet over medium heat, cook ground beef and chopped onion until beef is browned and onion is soft, about 6-8 minutes. Drain excess fat from the skillet.
03 - Stir in garlic powder, onion powder, kosher salt, and black pepper. Mix well to distribute seasonings evenly.
04 - Pour condensed cream of mushroom soup and milk into the skillet. Stir until combined and smooth. Add frozen corn kernels and frozen peas, mixing thoroughly.
05 - Spread the beef and vegetable mixture evenly across the bottom of the prepared baking dish. Sprinkle shredded cheddar cheese evenly over the top.
06 - Arrange frozen tater tots in a single, even layer over the entire surface of the casserole, covering the cheese completely.
07 - Bake uncovered for 40-45 minutes, or until tater tots are golden brown and crispy, and the filling is bubbling around the edges.
08 - Remove from oven and let casserole rest for 5 minutes before serving to allow it to set for easier scooping.