Preheat oven to 350 degrees.
Place oreos and hazelnuts in a food processor and process until evenly ground.
Drizzle melted butter in while pulsing the food processor.
Wrap outside of a 9-inch springform pan with aluminum foil and set it on a baking tray. Press oreo mixture into bottom of the pan and slightly up the sides.
Bake for 10 minutes, placing the baking tray in the oven too in case anything leaks out.
Lower oven temperature to 300 degrees.
Beat cream cheese with an electric mixer until smooth. Gradually beat in sugar.
Add heavy cream, vanilla, and salt and beat until smooth, scraping down the sides of the bowl to make sure everything is mixed evenly.
Beat in Nutella.
Add eggs and stir to mix them in with a rubber spatula. You don't want to overmix at this point.
Pour batter on top of crust. Place cheesecake inside a roasting pan. Be sure the bottom and sides of springform pan are wrapped well with aluminum foil. Pour water into the roasting pan so that it comes halfway up the cheesecake. Note; Instead of doing this, you can place a roasting pan filled with water.on the bottom rack of the oven.
Bake cheesecake for 60 minutes. Turn oven off. Do not open the door. Leave cheesecake in oven for 60 more minutes.
Remove cheesecake from waterbath and run a knife around the sides. Remove the sides of the springform pan. Refrigerate overnight.
To make glaze, place Nutella in a bowl. Bring cream to a simmer and pour over Nutella. Whisk until smooth. Pour over cheesecake. Use an offset spatula to spread it evenly.