Remove hash browns from freezer while preparing other ingredients to thaw. Lightly grease a 13x9 baking dish.
In a large frying pan over medium heat, cook and crumble the chorizo, about 7-10 minutes. Drain grease, if necessary, and set aside.
In a large bowl, beat the eggs and melted butter. Mix in the chorizo sausage, bell pepper and onion, and pour into baking dish. Add hash browns on top and sprinkle cheese on top of hash browns.
Bake at 350°F for 45 minutes. Serve with salsa, if desired.