Unroll pie crusts on lightly floured surface. Use rolling pin to roll each to 12-inch circle. Cut each crust into 8 (4-inch) circles with biscuit cutter, rerolling dough as needed. Place on parchment-covered baking sheets. Spoon 2 Tbsp. chicken mixture onto centre of each circle; brush edge with egg. Fold dough circles in half. Press tops lightly to remove excess air; seal edges with fork. Brush tops with remaining egg. Sprinkle with chili powder.