Preheat your oven to 350°F. Grease a 9x13-inch baking dish.
In a large mixing bowl, combine the thawed hash browns, sour cream, cheddar cheese, French onion dip, cream of chicken soup, garlic powder, onion powder, salt, and black pepper. Mix until well combined.
Spread the mixture evenly into the prepared baking dish.
In a separate bowl, combine the crushed cornflakes and melted butter. Stir until the cornflakes are evenly coated.
Sprinkle the cornflake mixture over the top of the potato mixture in the baking dish.
Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and the edges are bubbly.
Let cool for 5-10 minutes before serving.