Line a large baking sheet with foil and set aside. In a large bowl, combine the hazelnut cookie crumbs, finely chopped hazelnuts, and the Nutella. Using a spoon or your hands, stir the mixture together until completely moistened and sticky, making sure you grab the dry bits that tend to collect in the bottom of the bowl.

Using a Tablespoon-size cookie dough scoop, scoop out truffles and roll gently into balls. Place on the baking sheet about 1/2" apart. Repeat with remaining truffles. Once all truffles are formed, freeze the truffles for at least 30 minutes to 1 hour or until firm.

Once truffles have firmed up, melt the candy coating according to package directions or until smooth. Stir in the chopped hazelnuts. Using a fork, lower each truffle one at a time into the chocolate candy coating and coat completely. Use the fork to lift the truffle out of the chocolate mixture and tap excess chocolate off. Return the truffles to the baking sheet and let chocolate set before serving.