1. in 2 qt saucepan combine sugar and butter. cook over low heat stirring occaionally, until candy thermometer reaches 300*F (149*C) or a small amount of mixture dropped into ice water forms brittle strands 25-30 minutes.
2. spread on waxed paper-lined 15x10x1in jelly roll pan.
3. sprinkle chocolate chips over hot candy, let stand 5 minutes.
4. spread melted chocolate evenly over candy.
5. sprinkle with nuts, cool completely, break into pieces.
6. serve.