In large bowl, stir together sugar, flour, cinnamon and nutmeg until well combined. Add peach slices and lemon juice and stir until peaches are well coated.
Gently unroll pie crust and press into bottom and up sides of pie pan. Pour peach mixture into crust. Scatter chunks of butter over top. On lightly floured surface, gently unroll second pie crust. Cut into 3/4 in. strips. Place strips horizontally, then vertically, across the top of the pie, trimming so that each strip comes to the edge of the pie. Fold bottom crust over strips and pinch to seal. Beat egg with 2 tablespoons water until well combined. Brush over strips and edges of pie. Place on cookie sheet and bake 40-45 minutes or until crust is golden brown and filling is bubbly. Cool before serving.