Preheat oven to 375 degrees F. Grease a 9 x 13 baking dish with butter and set aside.
Peel and cube potatoes. Place in boiling water with 1 tsp. salt. Bring to a boil and cook until edible but firm; potatoes should be able to keep their cubed shape. (Approximately 20 minutes from the time you set them into a boiling pot.) Drain.
Empty cream of chicken soup into a bowl. Melt butter and thoroughly mix with soup.
In another bowl, add sour cream, shredded cheddar, green onions, salt and pepper. Add the soup mixture, and mix well.
Add potatoes to the bowl of creamy sauce and gently fold in just until potatoes are coated, being careful not to break the cubes apart. Gently transfer mixture to the greased 9 x 13 baking dish.
Crush the corn flakes; melt the butter and mix with the corn flakes until coated. Sprinkle over potato mixture in baking dish.
Bake at 375 degrees F for 45 minutes, or until potatoes bubble and corn flakes are a deep golden color. If they are getting too dark before the potatoes are done cooking, set a piece of foil over the top to prevent burning.