Preheat Oven: Preheat your oven to 350°F (175°C).
Cook the Sausage: Heat a skillet over medium heat. Add the sausage and break it into small pieces. Cook until no longer pink, then remove from heat and set aside.
Prepare the Dish: Grease a 9x13-inch baking dish with cooking spray. Spread the cooked sausage evenly over the bottom of the dish.
Make the Egg Mixture: In a large bowl, whisk together eggs, milk, garlic powder, salt, and black pepper.
Assemble the Casserole: Pour the egg mixture over the sausage. Sprinkle the shredded cheese evenly on top. Add the frozen tater tots, arranging them in a single layer for a crispy topping.
Bake: Place the casserole in the preheated oven and bake for 50 minutes or until the center is set and no longer jiggles.
Rest and Serve: Remove from the oven and let the casserole rest for 5 minutes before slicing and serving. Enjoy!