Preheat your oven to 350°F and spray a 9x13-inch baking dish with cooking spray.
Cook the breakfast sausage in a large skillet over medium heat, breaking it up as it cooks, until browned and fully cooked through (about 7-8 minutes). Drain any excess grease.
Spread the cooked sausage evenly in the bottom of your prepared baking dish. Sprinkle 1 cup of the shredded cheddar cheese over the sausage.
Arrange the frozen tater tots in a single layer over the cheese and sausage (don't worry if they're a little crowded).
In a large bowl, whisk together the eggs, milk, salt, pepper, and garlic powder until well combined. Pour this mixture evenly over the tater tots.
Bake uncovered for 40 minutes, then sprinkle the remaining 1 cup of cheese on top and bake for another 5 minutes until the cheese is melted and bubbly.
Let it cool for 5 minutes before serving. This gives the eggs time to set up so you get nice clean slices!