In a bowl, mix together all ingredients for filling and refrigerate until ready to assemble empanadas.
On a floured surface, roll out pie shells and cut into 4-inch circles (use all the pie dough by re-rolling scraps).
Place approximately 2 Tbsp of cheese and chicken mixture in center of dough circles. Fold each circle in half and crimp edges with a fork.
Place on a baking pan or cooking sheet and brush top of each empanada with egg yolk. Sprinkle top with salt and chili powder.
Bake 12 to 13 minutes at 400° F. Serve warm or at room temperature.
Servings: 6