Chicken Enchilada Bake

1 medium onion chopped
1-4 oz. can black olives chopped 
1-4 oz. can green chiles chopped 
1-2 cloves garlic chopped
oil
2 cups chicken broth
1-7 3/4 oz. can El Pato enchilada sauce
1 dozen corn tortillas
1 small cooked chicken shredded
1-16 oz. carton sour cream
10 oz. cheddar cheese grated
Saute onion, olives, chiles and garlic. In a bowl, mix chicken 
broth and El Pato sauce. Layer tortillas, chicken, onion mixture, 
sour cream, cheese and sauce. Repeat layers. Bake in oven for 1 
hour at 350 degrees.