In medium saucepan, combine marshmallow cream, sugar, milk, butter and salt. Bring to full boil, stirring constantly over moderate heat. BOIL 5 minutes over moderate heat, stirring constantly. Remove from heat.
Add the 12 ounces chocolate morsels. Stir until morsels are melted and mixture is smooth. Stir in nuts and vanilla. Pour into 8 inch square pan. Chill until firm.