Thaw frozen hash brown potatoes and place them in a large bowl mixing bowl.
In a smaller bowl, mix Cheez Whiz, onions, sour cream, cream of chicken soup. A few minutes in the microwave will help make this easy to stir together.
Pour this mixture over the potatoes and gently stir to combine. Add salt and pepper to taste, Keep in mind, the soup and cheese are salty, so be cautious with added salt.
Pour the potatoes into an 9 x 13 inch casserole dish.
In a large bowl, gently combine melted butter with corn flakes. Spread this mixture over the potatoes.
Bake 350 degrees for 40 - 45 minutes. Mixture needs to be nice and steamy and Corn Flakes starting to brown.
Notes
I made this recipe with shredded frozen hash browns. It would most certainly work with country style cubed hash browns. All that would change is the texture.