Crumble the wafers and add the hazelnuts and Nutella to them. Stir well and leave the mixture in the fridge for at least 30 min.
From the mixture, form balls the size of a small walnut. Leave them in the fridge for 30 min.
Melt the chocolate in a bowl. Add the hazelnuts and oil. Stir well.
Take the balls out of the fridge and dip each in the chocolate-hazelnut mixture.
Place them onto a platter laid out with baking paper. Leave in the fridge to harden and then arrange in paper cups.