In heavy saucepan, combine corn syrup, vinegar, butter, evaporated milk...cook over medium heat; bring to boil (stirring constantly) and continue to boil until you reach soft ball stage. A good tip is to drop a pinch into cold water, if it stays together, the ingredients can be removed from the heat. After removing from heat, add marshmallow creme and peanut butter. Pour over 1 cup chocolate chips, then into foil-lined 9" X 13" cake pan. Sprinkle rest of chocolate chips on top for swirl effect.