Butter 9-inch square pan. Melt 1 cup butter in 2-quart saucepan, slowly stir in sugar. Add syrup and water. Stir. Cook over medium heat (290ºF. on candy thermometer) or until a little mix dropped in cold water becomes brittle. Add 1 cup walnuts, cook 3 minutes more, stir. Pour into pan. Remove when cold. Place on wax paper. Melt chocolate bits. Coat toffee with chocolate. Sprinkle with nuts, allow to set about 1 minute, turn over and repeat coating. Break into bite-size pieces.