Prepare 9×13-inch pan by lining with aluminum foil or parchment paper. Melt butter over medium heat in heavy 2 to 3 quart saucepan.
Stir in sugar, corn syrup and espresso. Cook over medium heat stirring constantly until sugar is dissolved and mixture comes to a boil.
Clip on candy thermometer and continue to stir occasionally until temperature reaches 300°F (hard crack stage.)
Pour mixture into prepared pan.
Sprinkle with chocolate chips, wait 2 minutes; spread chocolate evenly over candy. (If uniform piece size desire, score candy into 1-inch square pieces with table knife.) Sprinkle nuts over chocolate, shaking dish from side to side to coat. Gently press nuts into chocolate.
Let candy stand at room temperature to cool completely. Break into pieces. Store in an airtight container.