Preheat oven to 375 degrees F. In a large bowl, mix graham cracker crumbs, sugar and melted butter until blended. Press mixture into an 8 or 9 inch pie pan. Bake for 7 minutes and let cool completely.
In a large bowl, beat together cream cheese and whipping cream until thickened and smooth. Add Nutella and stir until combined. Spoon into crust and spread evenly. Cover and refrigerate for at least 3 hours.
Before serving, top with marshmallows and press them gently into chocolate filling. Broil for 1-2 minutes or until marshmallows are golden brown.
Melt chocolate chips in a microwave safe bowl for 1-2 minutes and stir until smooth. Drizzle melted chocolate over the top of the pie.