Place the chocolate chips, marshmallow crème, vanilla and nuts if using in a large bowl and set aside. Get your beaters ready. Grease a 9 x 13 pan and set aside.
In a large saucepan add the sugar, evaporated milk and butter. Bring to a boil and reduce heat and cook stirring constantly for 4 minutes.
Remove from heat and immediately pour over chocolate chip mixture. Beat with mixer until all ingredients are well incorporated. Pour in greased pan and refrigerate to harden up about 3 hours. Cut into squares