Preheat the oven to 350 degrees. 

Saute the sausage in a skillet over medium high heat on the stove until completely browned. Remove and set aside. 

In the same skillet, heat the hashbrowns until lightly browned and mostly defrosted, about 8-10 minutes. 

Layer the hashbrowns in the bottom of a 9x13 greased casserole dish. 

Add the sausage on top of the hashbrowns. 

Sprinkle the cheese over the meat, and add the green chilis on top of the cheese. 

In a large mixing bowl, combine the eggs, milk, onion powder, garlic powder and salt and pepper to taste. Whisk to combine well. 

Pour the egg mixture over the casserole. 

Bake uncovered for 35-40 minutes until the eggs are completely set.