Place chicken breasts in baking pan, cover with foil and bake at 350 for one hour. Shred when cool enough to handle and set aside. Reserve pan juices. In bowl, mix soups, salsa, milk and onion. In 9x13" pan, pour reserved juice (you can add some chicken broth here if you need to, there should be enough juice to cover bottom of pan). Arrange half of corn tortillas in bottom of pan. Layer half or chicken over tortillas, half of the sauce, half of the olives and half of the cheese. Repeat, ending in cheese. Cover with foil and bake at 350 for 1 1/2 hours. Remove foil and bake half hour longer. Good served with refried beans and cornbread.