Place sugar, butter and milk in a heavy-duty medium saucepan over medium heat. Bring to a rolling boil and cook, stirring constantly, until a temperature of 234 degrees is reached.
Remove from heat. Stir in chocolate chips and marshmallow cream until completely melted.
Stir in vanilla extract and pecans.
Pour in a 9x9 pan that has been line with foil and overlaps the sides. Let cool completely in pan. Remove from pan by grabbing foil. Place on a cutting board and cut into small serving pieces.