Preheat oven to 400 degrees F.
In a medium bowl, stir to combine all filling ingredients. Set aside for 15 minutes.
In a large bowl, stir together pie crust mix and 1/3 cup chilled peach nectar until dough forms a ball. Split dough in half, and form into 2 disks.
On a lightly floured surface, use a rolling pin to roll dough 1 1/2-inches larger than an upside-down 9-inch pie pan. Fold dough in half and unfold over pie pan. Press onto bottom of pan.
Fill pie shell with peach filling mixture; set aside.
Roll out remaining dough and place over filled pie shell. Pinch the edges of the pie together or crimp with a fork. Trim away any excess dough.
Lightly beat egg with 1 tablespoon peach nectar or water to make egg wash. Use a pastry brush to lightly brush top of pie with egg wash. Sprinkle with sugar. Cut slit in center to vent pie.
Bake in preheated oven for 45 to 60 minutes or until crust is golden and filling is bubbling through vent. If edges get too brown, cover edges with foil to prevent burning.
Cool before slicing.