In a skillet over medium heat, cook the sausage until browned. Drain any excess grease and set aside.
In a large bowl, whisk together the eggs, milk, salt, pepper, garlic powder, and paprika.
Grease a 9x13-inch baking dish. Spread the hash browns evenly, followed by the cooked sausage, bell peppers, and onions. Sprinkle cheddar and mozzarella cheese on top. Pour the egg mixture over everything, making sure it’s evenly distributed.
Preheat the oven to 375°F (190°C) and bake for 40-45 minutes, or until the eggs are set and the top is golden brown. Let it cool slightly before slicing and serving.