2 1/3 cups granulated sugar
2 cups butter (no substitutes)
1/2 cup plus 2 tablespoons water
2 tablespoons light corn syrup
1 1/2 cups chopped walnuts or pecans, toasted
1 cup (6-ounces) semi-sweet chocolate chips
Butter 15x10x1-inch jelly roll pan. Combine all ingredients except nuts and chocolate chips in heavy 3-quart saucepan. Cook over medium heat, stirring constantly, until butter is melted.
Reduce heat to medium-low. Continue cooking, stirring occasionally, until candy thermometer reaches 300°F or small amount of mixture dropped into cold water forms hard brittle strands (25 to 40 minutes). Stir in 1 cup nuts.
Pour mixture into prepared pan; spread to desired thickness. Sprinkle chocolate chips over hot candy; let stand 5 minutes. Spread melted chocolate evenly over candy. Sprinkle with nuts. Cool completely (at least 3 hours). Break into pieces. Store in airtight container in a cool dry place up to three weeks.