Cheesy Tater Tot Meatloaf Casserole

Ingredients:

1 pound ground beef
1 egg
1/2 cup bread crumbs
1/4 cup milk
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon salt
1/4 teaspoon black pepper
2 cups shredded cheddar cheese, divided
1 package (32 ounces) frozen tater tots
1 can (10.5 ounces) condensed cream of mushroom soup
1/2 cup sour cream
1/4 cup chopped green onions (optional)