Preheat your oven to 375 and grease a 9x13 baking pan.
In the pan, first mix together your sour cream, cheese and cream of chicken soup until mixed well.
Add in thawed potatoes and stir until combined.
Wipe off edges of pan and place in oven for 35 minutes.
Check the potatoes at 45 minutes and if still not cooked, place back in oven at intervals of 5-10 minutes until cooked and golden brown on top.
Once cooked through, melt your butter in a small bowl and combine with corn flakes, then place on top of your potatoes. Bake for another 5 minutes with corn flakes on top until crispy.