Heat oven to 400 degrees F. In bowl, mix nectarines, plums, granulated sugar, nuts, brown sugar, cornstarch, lemon juice, cinnamon, nutmeg and pepper.
Unfold 1 pastry round. Roll out to 12-inch circle. Transfer to deep-dish pie dish. Unfold second pastry round. Roll out to 12-inch circle. With sharp knife or pastry cutter, cut circle into 3/4-inch-wide strips.
Spoon filling into pie dish. Over top of pie, weave strips in lattice pattern. Crimp edge of crust together with end of strips; flute edge decoratively, if desired.
Brush crust with milk; sprinkle with sugar.
Bake in 400 degree F oven 15 minutes. Reduce to 375 degrees F. Cover edge with foil. Bake 50 to 55 minutes, until filling is bubbly and thickened. Let cool on rack at least 45 minutes. Serve slightly warm or let cool completely. Makes 12 servings.