In a large skillet, over medium high heat brown the sausage. Remove the cooked sausage with a slotted spoon and place in the bottom of a 9 x 13-inch baking dish. Sprinkle the shredded cheese over top the sausage.
In a large bowl or glass measuring cup, whisk together the milk, eggs, onion powder, garlic powder, salt, and pepper. Pour evenly over the cheese and sausage. Layer the top with frozen tater tots, keeping them all the same direction.
Bake in a preheated 350 degree F oven for about 35 minutes. Top with an additional ½ cup of shredded cheese, crumbled bacon, and bake for another 5-10 minutes. Just until the cheese is melted and the top is golden brown. Garnish with finely chopped green onion. Serve immediately.