Preheat oven to 400 degrees F.
Line a baking sheet with parchment paper or spray with non-stick cooking spray.
In a large bowl, combine chicken, cream cheese, shredded cheese, green chilies, tomatoes with green chilies, green onions, salt and pepper. Stir until well combined.
Unroll one pie crust on a lightly floured surface.
Using a 3-inch biscuit or cookie cutter, cut out rounds. Re-roll dough as needed.
Repeat using both pie crusts in package.
Lightly brush the outer edge of each round with water.
Place one heaping teaspoon of chicken mixture in the center of each round.
Fold dough over the filling and press edges together with a fork to seal.
Repeat with remaining rounds and mixture.
Place the empanadas on baking sheet and light brush the tops with beaten egg.
Bake for 12-15 minutes.