Preheat oven to 350 degrees F.
In a large mixing bowl, combine hash browns, egg whites, milk, onion, salt, pepper, onion powder, garlic powder, ham and 1/2 cup shredded cheese.
Pour mixture into a 9x13-inch baking pan sprayed with nonstick cooking spray.
Top with remaining 1/2 cup cheese.
Cover with foil and bake for 1 hour.
Remove foil and bake for an additional 10 minutes.
Let rest for a few minutes before serving.