Preheat the oven to 325 degrees F. Place the eggs, sugar and vanilla in a bowl and whip until thick and light. Whip in the ricotta, cream, flour, nutmeg and orange zest until well combined. Pour the mixture into the piecrust. Arrange the nectarine wedges on top in spiral-like fashion. Bake for 60 minutes, or until the filling is set. Cool to room temperature. Chill the pie well before serving.