In a large bowl, whisk the eggs with the salt and pepper
Add the sour cream to the egg mixture and whisk well to combine.
Add the thawed hash browns to a casserole dish, along with the cooked chicken and 1 1/4 cup of the cheese.
Pour the egg and sour cream mixture over the potatoes, chicken and cheese, and top with remaining cheese.
Bake, covered at 375 degrees F for 30 minutes, then remove cover and bake for an additional 15-20 minutes or until eggs are set.
Brown the hash browns in a skillet before adding them to the casserole to avoid them being too watery or mushy.