Preheat the oven to 350ºF and lightly spray a 9x13-inch baking pan with cooking spray to prevent sticking. Set the prepared baking dish aside for later assembly.

In a large skillet over medium heat, cook the breakfast sausage until it is browned and no longer pink, breaking it up as it cooks. Drain any excess fat and set the cooked sausage aside. I like to make sure the sausage is nicely browned for extra flavor.

In a large mixing bowl, toss together the frozen potato tots, cooked sausage from Step 2, mozzarella cheese, and shredded Cheddar cheese until evenly mixed. Transfer this mixture into the prepared 9x13-inch baking pan, spreading it into an even layer.

In a separate bowl, whisk together the eggs, milk, salt, pepper, garlic powder, and onion powder until fully combined. Pour this egg mixture evenly over the tater tot mixture in the baking dish. This ensures the casserole bakes up light and fluffy.

Bake the casserole uncovered in the preheated oven for 60 to 70 minutes, or until the eggs are set and the top is golden brown. Let it cool slightly before serving for the best slices. Sometimes I let it rest for a few minutes so the pieces hold together nicely when cut.