Preheat oven to 350°F. Grease a 13x9-inch baking dish with nonstick spray or butter.
In a large skillet over medium heat, cook breakfast sausage or bacon until browned and fully cooked. If using sausage, crumble it as it cooks. Once cooked, drain excess grease and set aside. If using bacon, crumble after cooked.
In a large bowl, whisk eggs until well blended.
Add green onions, cheddar cheese, cottage cheese, Swiss cheese, salt, pepper and the cooked breakfast meat. Mix again until well combined.
Fold the thawed hash brown potatoes into the mixture.
Pour the mixture into the prepared dish and spread evenly.
Bake 35-40 minutes or until a knife inserted near the center comes out clean. Rest 10 minutes before serving.