In a medium, heavy bottomed pot, heat sugar, evaporated milk and butter over medium high heat. Bring to boil and continue boiling for 4 minutes.
Remove from heat and stir in remaining ingredients. Stir until marshmallows and chocolate have melted and mixture is smooth except for the nuts. Pour into prepared pan.
Refrigerate until hardened and set. Remove from pan and peel away foil. Cut into small squares and store in air tight containers, covered with plastic wrap or wax paper until ready to serve.