Preheat oven to 315F. Prepare a 9-inch spring form pan for a water bath: double wrap the bottom of the pan with foil to ensure that water does not seep in.

Prepare the chocolate crust. Place the chocolate graham crackers into a food processor and pulse into fine crumbs. Add the melted butter and pulse again until crumbs are well coated. Transfer the crumbs into prepared pan and using a large spoon or the back of your hand, press the crumbs into a firm and even crust.

Next, prepare the filling. Place softened cream cheese into a stand mixer bowl and whisk for about 7 to 9 minutes, until cream cheese is light and fluffy. Next, add the sugar, eggs, vanilla, hazelnut liqueur, sour cream and heavy cream. Whisk again for 5 minutes, scraping down the sides of the bowl often. Finally, add the entire jar of Nutella into the batter. Mix again until well-combined.

Last, fold in the chopped hazelnuts and crushed cookies. Pour the filling over the prepared chocolate crust and level off the top with an off-set spatula.

Prepare a water bath. Place the cheesecake pan onto a baking tray with deep sides; partially fill the pan with water. Bake the cheesecake in preheated oven for 1 hour 45 minutes, up to 2 hours, until edges are set and center is slightly wobbly. Turn oven off, set the oven door ajar and allow the cheesecake to cool in the oven for 1 hour. Then, remove the cheesecake from the oven and allow it cool slowly for a few hours before refrigerating overnight.

Once cheesecake has set, remove the spring form and transfer the cake onto a cake stand. Prepare the chocolate ganache for garnish. Heat the heavy cream until hot, then add the chocolate chips and stir until smooth and melted. Pour the chocolate ganache over the top of the cheesecake and level with an off-set spatula.