Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish.
In a large bowl, mix the thawed hash browns, cream of chicken soup, sour cream, shredded cheddar cheese, melted butter, salt, pepper, and garlic powder.
Spread the mixture evenly in the prepared baking dish.
Sprinkle the crushed cornflakes or crispy fried onions evenly over the top.
Bake for 45-50 minutes, or until the top is golden brown and bubbly.
Let cool slightly before serving. Enjoy!