Combine the cream, sugar and Nutella in a small saucepan and set on medium heat. Stir continuously until the Nutella dissolves (a hand whisk can help). Remove the mixture from the heat just before it reaches boiling temperature.
Soak the gelatin sheets in cold water. Aside, warm up the milk. When the gelatin has bloomed, drain it and squeeze any excess water. Stir it into the hot milk. Pour gelatin mixture into the saucepan and stir all the ingredients together.
Divide the mixture between moulds and place in the fridge to set for a minimum of 2 hours. When hardened, unmould by flipping onto a serving plate and top with chopped hazelnuts.
Notes
The nutritional information shared here is obtained using an online calculator and therefore only to be used as a guideline.