Season chicken breasts with salt and pepper. Wrap in foil with some onion and 1 – 4 oz. can of Ortega green chiles. Bake at 350 degrees until fully cooked, reaching an internal temperature of 165 degrees F.
Remove from oven and open foil to cool. Once cool, slice the chicken. Be sure to save any juices/broth.
Combine the saved broth, 1 – 4 oz. can Ortega green chiles, soups, and sour cream in a medium bowl. Stir well to combine.
In a 13×9 inch casserole dish, layer the bottom with half of the tortillas, half of the sliced chicken, half of the soup mixture, and one third of the cheese. Repeat this process.
Top with remaining cheese and the black olives. Bake at 350 degrees for 1 hour.
Remove from oven, slightly cool, and serve. Enjoy!