Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish with cooking spray or butter.

In a large skillet over medium heat, cook the crumbled breakfast sausage until browned and cooked through, about 5-7 minutes. Drain excess fat and set aside.

In a large bowl, combine the thawed hash browns, cooked sausage, cheddar cheese, sour cream, eggs, milk, garlic powder, onion powder, salt, black pepper, and paprika. Mix until well combined.

Pour the mixture into the prepared baking dish, spreading it evenly.

Bake in the preheated oven for 30-35 minutes, or until the casserole is set and the top is golden brown.

Remove from the oven and let it cool for about 5 minutes. If desired, sprinkle with chopped green onions before serving.