In a crock pot mix taco seasoning with water, add chicken and cook until tender (approximately 6 hours).
Remove cooked chicken from crock pot and shred. Set aside.
Place 1/2 tortillas on the bottom of an 8x12 greased baking pan.
Layer 1/4 cup Mexican cheese, chicken, peppers, onions (and any additional ingredients you want such as olives or jalapenos). Add 1/2 cup Mexican cheese and finish layering with the remaining tortillas.
Pour fajita sauce over the tortillas.
Cover with foil and bake for 20 minutes at 375 degrees F.
Remove casserole from oven, top with Queso Fresco Cheese and bake for an additional 10 minutes covered.
Remove from oven and allow to rest for 10 minutes before cutting.
Garnish with diced green onion and 1 tablespoon of chopped cilantro to serve.