Grease a 9-inch square baking pan, set aside. In large saucepan combine sugar, butter, evaporated milk, Fluff and salt. Stir over low heat until blended. Bring to a full-rolling boil being careful not to mistake escaping air bubbles for boiling.Boil slowly, stirring constantly, 5 minutes, (soft ball stage). Remove from heat, stir in vanilla and chocolate until chocolate is melted. Add nuts. Turn into greased pan and cool. Makes 2-1/2 pounds. Microwave Fudge Instructions: 1. Combine sugar, margarine, milk, Fluff and salt in a 4-qt microwave safe bowl. Microwave at medium high for 2-1/2 minutes, remove and stir until blended. 2. Microwave at medium high for 5 minutes; remove and stir until smooth. 3. Repeat step 2. 4. Microwave at medium high for 6 minutes; remove and stir in chocolate, vanilla and nuts for 5 minutes until thick. Turn in buttered 9x9 inch square pan and cool. Important: Instructions are for a 600 watt microwave oven. For a different size oven, adjust cooking accordingly