Saute onions, then add vegetables, and garlic in that order.
Place chicken, tomatoes, enchilada sauce, onion, green chiles, and garlic into a slow cooker. Pour in water and chicken broth, and season with cumin, and bay leaf. Stir in corn and cilantro. Cover, and cook on medium low setting for 30 mins.
Preheat oven to 400 degrees F (200 degrees C).
Lightly brush both sides of tortillas with oil. Cut tortillas into strips, then spread on a baking sheet.
Bake in preheated oven until crisp, about 10 to 15 minutes. To serve, sprinkle tortilla strips over soup.