Preheat oven to 400 degrees F. Line a sheet pan with parchment paper.
In a medium bowl, add two cups of shredded chicken. Sprinkle with taco seasoning and stir so chicken is evenly covered with taco seasoning.
In the bowl with the chicken, add the green chiles, sour cream, and ½ cup of shredded cheese.
Stir all ingredients together until all are evenly distributed.
In a small bowl, add one egg and a tablespoon water and stir.
Lay the flour tortillas out flat on the parchment paper on the sheet pan. (You may have to do this in 2 batches.)
Brush the edges of each tortilla with the egg wash.
Using an ice cream scooper or large spoon, spoon ¼ cup of the chicken mixture onto each tortilla.
Sprinkle 1 tablespoon shredded cheese over the top of the chicken on each tortilla. Repeat for each tortilla.
Fold the other half of the tortilla over the top of the chicken and cheese. Repeat for each empanada.
Brush each empanada with the egg wash.
Make 3 slits in the top of each empanada.
Bake in a preheated oven for 15 minutes. Remove from oven and serve hot.