Mix 2/3 cup undiluted Carnation evaporated milk, 1 2/3 cups sugar and 1/2 teaspoon salt in a saucepan over low heat. Heat to boiling, then cook 5 minutes, stirring constantly. Remove from heat. Add 1 1/2 cups (16) diced marshmallows, 1 1/2 cups semi-sweet chocolate pieces, 1 teaspoon vanilla and 1/2 cup chopped nuts. Stir 1-2 minutes until marshmallows melt. Pour into buttered 9 inch pan.