Spread the frozen hash browns along the bottom of a 9X13 baking dish that's been sprayed with non-stick baking spray.
Add the diced ham, cheese and chopped onions.
In a large mixing bowl combine eggs, evaporated milk, green onions, salt and pepper.
Whisk until fully combined.
Pour the egg mixture on top of the hash browns.
Bake in a preheated 350°F oven for 50 to 60 minutes or until the center is set and firm.
Allow to cool slightly before serving.
Notes
If you are making this ahead of time, you can cover and store it in the refrigerator for up to two days until ready to bake. You can freeze this casserole before baking as well. Cover tightly and freeze for up to 3 months.