Line a 9x13 baking pan with foil. Grease all sides of the foil with butter or nonstick baking spray. In a large, heavy bottom sauce pan add sugars, milk, butter and bring to a full boil. Boil for 5 minutes. Remove from fire and add vanilla, chocolate chips, marshmallow crème, and nuts. Stir until incorporated and pour into prepared baking pan. When cool, cut into squares.