Combine graham cracker crumbs, melted butter, sugar, and salt in a medium bowl. Mix until the texture resembles wet sand.
Press the mixture firmly into the bottom of a 9-inch springform pan using the flat bottom of a measuring cup to create an even layer.
Place the crust in refrigerator while preparing the filling.
In a large bowl, beat softened cream cheese until completely smooth and free of lumps, about 2-3 minutes.
Add Nutella to the cream cheese and beat until fully combined, scraping down the sides of the bowl as needed.
Mix in powdered sugar and vanilla extract until completely combined.
Fold in the whipped cream using gentle, sweeping motions to maintain air bubbles for a lighter texture.
Pour filling over the chilled crust, smoothing the top with an offset spatula.
Cover with plastic wrap (avoid touching the surface) and refrigerate for at least 4 hours, preferably overnight.
Before serving, warm 1/2 cup Nutella until pourable and drizzle over the cheesecake.
Sprinkle with toasted hazelnuts and add dollops of whipped cream if desired.