In a medium bowl, whisk together the hazelnut flour, sweetener, cocoa powder, and salt. Stir in the melted butter until the mixture begins to clump together.
Press the mixture firmly and evenly into the bottom and up the sides of a 9 inch pie plate. Refrigerate while preparing the filling.
Filling
Prepare the sugar free chocolate hazelnut spread according to the directions.
In a large bowl, beat the cream cheese until very smooth, about 1 minutes. Beat in ½ cup of the sweetener, then beat in the Nutella and hazelnut extract until well combined.
In another large bowl, beat the whipping cream with the remaining ¼ cup sweetener and the vanilla extract until it holds stiff peaks. Fold two thirds of the whipped cream into the Nutella mixture until no streaks remain.
Spread the filling in the prepared crust and refrigerate until firm, 2 to 3 hours.
Spread the remaining whipped cream over the center of the pie and sprinkle with chopped hazelnuts.
Notes
Storage Information: Store the pie, tightly covered, in the fridge for up to 5 days. This pie can also be frozen for up to 2 months. I recommend adding the final layer of whipped cream after thawing.