Creamy Chicken Enchiladas

4 chicken breasts
1 Tbsp. olive oil
2 cloves garlic, minced
1 onion, finely diced
1 serrano pepper, seeded & diced
1 large tomato, diced
1/2 C. sour cream
1 C. shredded cheese
1/2 C. water
4 large tortillas or 8 small tortillas
1/2 can olives, drained & sliced
19oz can green enchilada sauce

-Preheat oven to 375
1.  Season chicken with salt & pepper and cook thoroughly.  Remove from pan and shred. 
2.  Add oil, garlic, onion, serrano pepper and tomato to pan and cook on medium heat until onion is translucent.  Add shredded chicken, sour cream, 1/2 C. cheese and water to pan and simmer 15 minutes.
3.  Divide mixture evenly among tortillas.  Pour 1/3 of the enchilada sauce on the bottom of a 9x13" pan, add enchiladas and cover with remaining sauce.  Top with remaining cheese and olives.  Cover with foil and bake for 30 minutes covered then remove foil and bake another 5 minutes uncovered.  Let sit 5-10 minutes before serving.