Line a 8-inch-square baking pan with foil.
In medium, heavy-duty saucepan, combine sugar, evaporated milk, butter and salt.
Bring to a full rolling boil over medium heat, stirring constantly.
Boil, stirring constantly, for 4 to 5 minutes and remove from heat.
Stir in marshmallows, morsels, nuts and vanilla extract.
Stir vigorously for 1 minute or until marshmallows are melted.
Pour into prepared baking pan and refrigerate for 2 hours or until firm.
Lift from pan and remove foil.
Cut into 48 pieces.