Preheat the oven to 375°F.
Lightly coat a 9x13-inch baking dish with nonstick cooking spray.
Place the pork breakfast sausage in a large skillet over medium heat.
Cook the sausage until fully browned and no longer pink.
Break the sausage into small crumbles as it cooks.
Drain any excess grease from the skillet.
Set the cooked sausage aside.
In a large mixing bowl, add the eggs.
Add the heavy cream or whole milk.
Add the salt, black pepper, and garlic powder.
Whisk the mixture until the eggs, dairy, and seasonings are fully combined.
Arrange the frozen tater tots in an even layer across the bottom of the prepared baking dish.
Sprinkle the cooked sausage evenly over the tater tots.
Sprinkle the shredded cheddar cheese evenly over the sausage layer.
Pour the egg mixture evenly over the tater tots, sausage, and cheese.
Cover the baking dish tightly with aluminum foil.
Place the covered casserole in the preheated oven.
Bake for 40 minutes.
Remove the foil from the baking dish.
Continue baking for an additional 15 to 20 minutes, or until the center is fully set and the eggs are cooked through.
Check the casserole around the 40 to 45-minute mark, as oven temperatures may vary.
Remove the casserole from the oven.
Allow the casserole to rest for 5 to 10 minutes before slicing.
Serve hot with sour cream, chopped tomatoes, salsa, cooked crumbled bacon, green onions, or hot sauce, if desired.