Place partially thawed corn in crockpot. Add the minced onion, garlic powder and undrained green chilies. Stir gently to combine.
Cube the butter and cream cheese and place cubes on the surface of corn. Set the crock pot on low and cook for 3-4 hours. Stir after all butter and cream cheese is melted to incorporate. If it looks a bit dry at this time, add a few more cubes of cream cheese.