Hash Brown Chicken Casserole

Name: Hash Brown Chicken Casserole
Ingredients: 16 ounces (1 small bag) shredded hash browns, fresh or frozen (thawed; I prefer Ore Ida frozen or Simply Potatoes fresh); 3 cups shredded, cooked chicken; 2 cups (10 ounces) frozen green beans (thawed); 2 cups (8 ounces) sharp cheddar cheese (grated, divided; you may use mozzarella, Monterey Jack, or Colby); 2 cups (16 ounces) sour cream (may also use Greek yogurt); 1 can (10¼ ounces) cream of chicken condensed soup (or use homemade condensed chicken soup); 1 cup onion (finely chopped; 1 small onion); ¼ teaspoon black pepper