Make the Crust

1. In a food processor, pulse the graham crackers into a fine crumb. Add the hazelnuts, and pulse until the nuts are fully incorporated but still have a bit of texture to them. Pour the mixture into a large mixing bowl, and stir in the cinnamon sugar and salt, followed by the melted butter, until fully combined. The crust mixture should be crumbly, and should stick together when pressed between two fingers.
2. Press the crust into the bottom of a non-stick, lightly-greased or parchment paper-lined 9-inch spring form pan to form an even layer. Set aside in the refrigerator to chill.

Make the Filling

1. Using a hand-held or stand-up mixer, cream together the cream cheese and half of the powdered sugar until light and fluffy. Add the vanilla and stir to combine. Set aside.
2. Meanwhile, whip together the cream and the remaining powdered sugar. Gently fold the whipped cream into the cream cheese mixture and stir to combine.
3. Pour the filling into the pan, and gently spread into an even layer.
4. Toss the nectarine slices and blueberries with the lemon juice, and arrange in a layer on top of the cream filling. Freeze for an hour or two until the filling has firmed up. Remove the sides of the spring-form pan, slice into wedges and serve chilled.