1. In a double boiler, combine chocolate, butter, heavy cream and Nutella. Heat until chocolate is completely melted.
2. Remove chocolate mixture from heat.
3. Whisk Frangelico.
4. Pour mixture into a shallow dish and cover with plastic wrap. Refrigerate for about 2 hours. If you refrigerate longer than two hours, the mixture will be too hard to work with. If this occurs, allow the mixture to sit at room temperature until they are pliable enough to work with.
5. Line a baking sheet with parchment paper.
6. Using a small scoop  or a melon baller, scoop out chocolate mixture, roll into one inch balls, and place on prepared baking sheet. Continue with remaining chocolate mixture.
7. Roll balls in chopped hazelnuts.
8. Refrigerate truffles until ready to serve.

These truffles can be stored in a sealed container in the refrigerator for 3-4 days or can be frozen for up to 3 months.