Pour Nutchello, rum, and Frangelico into a cocktail shaker with ice and shake to combine.
Place walnuts ans coconut in a blender or food processor and pulse until fully combined and fine. Set aside.
Dip 4 martini glasses into chocolate syrup to rim. Dip in walnut mixture to create the icing rim.
Swirl each martini glass with chocolate syrup.
Pour cocktail mixture into each martini glass and serve.