For the crust:

1. In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter. Stir until the crumbs are evenly coated.
2. Press the mixture into the bottom of a 9-inch springform pan or pie dish to form an even crust. Use the back of a spoon to press it down firmly.
3. Chill the crust in the refrigerator for at least 30 minutes to set.

For the cheesecake filling:

1. In a large mixing bowl, beat the softened cream cheese until smooth and creamy, about 2-3 minutes.
2. Add the Nutella and powdered sugar to the cream cheese, and continue beating until well combined.
3. In a separate bowl, whip the heavy cream and vanilla extract together until soft peaks form.
4. Gently fold the whipped cream into the Nutella mixture until fully incorporated.
5. Pour the cheesecake filling into the chilled crust and spread it evenly with a spatula.
6. Refrigerate the cheesecake for at least 4 hours, or preferably overnight, to allow it to set completely.

For garnish (optional):

1. Once the cheesecake is fully set, drizzle with additional Nutella or chocolate hazelnut spread for extra indulgence.
2. You can also top the cheesecake with whipped cream, chopped hazelnuts, or chocolate shavings for added texture and flavor.