Line a 9 inch square pan with enough aluminum foil to extend a little past the edges, and butter the foil.
Place chocolate chips in a glass bowl, and cook in the microwave, stirring every 20 to 30 seconds until melted and smooth.
Spread the melted chocolate in the bottom of the prepared pan. Set aside in the refrigerator to cool while you make the candy part.
In a small saucepan over medium heat, combine the sugar, butter, hazelnuts and corn syrup. Bring to a boil, stirring to blend as the butter melts.
Heat the mixture to 250 to 265 degrees F (121 to 129 degrees C), or until a small amount of syrup dropped into cold water forms a rigid ball.
Pour over the cooled chocolate, and spread into an even layer. Return to the refrigerator to cool. When completely cool, break into bite size pieces, and store in an airtight container.
