Preheat oven to 325F. Grease the bottom of a 8x8 -inch baking pan with butter or line it with parchment paper; set aside.
For the base:
In a food processor, process the graham crackers into fine crumbs. Add the melted butter and pulse a couple of times to fully incorporate. Pour into the lined baking pan and gently pat down evenly with hands or base of measuring cup. Bake for 5 mins. Remove from oven and pour cream cheese mixture on it.
For the cheesecake: While the base is baking, place the cream cheese and sugar in stand mixer (or by hand). Beat for 2 minutes until light and fluffy. Add eggs one at a time, beating in between. Lastly, add vanilla and beat to combine until the mixture is smooth and lump free. Pour mixture onto the baked graham cracker crust and smooth into a single layer. Drop large spoonfuls of Nutella on top of filling and swirl gently with a knife.
Bake 30 minutes or until the center only slightly jiggles. Remove from the oven and cool completely then refrigerate for at least 3 hours (or freezer for 1 hour). Once set, remove from pan using the parchment lining and slice into 9 bars.