Pre-heat the oven to 350F and spray a 9x11 casserole dish with non-stick spray.
Heat a cast iron skillet over medium heat and cook the Italian sausage, breaking it up as you go. Set aside.
Next, cook the hash browns until browned on both sides and set aside.
Whisk the eggs, salt, pepper, garlic powder and milk together in a large bowl.
Layer the hash browns in the baking dish, followed by the cooked sausage, then add the diced hatch chiles and lastly the cheese.
Next, pour the egg and milk mixture over the casserole.
Bake at 350F for about 25-30 minutes until the eggs are set.