Line 8-inch square baking pan with foil. In 2-quart saucepan, combine sugar, marshmallow creme, milk, butter, Kahlua and salt. Bring to a rapid boil, stirring constantly for 5 minutes. Remove from heat; add all chocolate. Stir until melted. Add nuts and vanilla. Turn into prepared pan. Refrigerate until firm. To serve, cut in squares. Make about 2-3/4 pounds.