1. Place chicken, tomatoes, enchilada sauce, onion, green chiles, and garlic into a slow cooker. Pour in water and chicken broth, and season with cumin, chili powder, salt, pepper, and bay leaf. Stir in corn and cilantro. Cover, and cook on Low setting for 6 to 8 hours or on High setting for 3 to 4 hours.
2. Preheat oven to 400*F.
3. Lightly brush both sides of tortillas with oil. Cut tortillas into strips, then spread on a baking sheet.
4. Bake in preheated oven until crisp, about 10 to 15 minutes. To serve, sprinkle tortilla strips over soup.
My Note: This is AS CLOSE TO AUTHENTIC as possible. I love "cheater" recipes like this. Open a few cans, dump it in, and wa-la! In Mexico we buy the right variety of peppers, cook them down, throw them in the blender, etc to make meals like this. This saves all that hassle for a genuine taste. My entire family says it's as good as the tortilla soups served here in local restaurants. That's the highest compliment a recipe can be given! Don't bother cooking the chicken ahead of time. Throw it in with the rest in the beginning and shred it 2-3 hours later. Hint: serve with lime juice, a tsp of sour cream, chopped avocados, or pork rind along with the cheese to really eat it like a Mexican. BTW, I bought bagged tortilla chips and worked fine.
I threw in a couple of frozen chicken breasts rather than cooking them first and saved myself a step. (I shredded them towards the end.) I also used bagged tortilla chips instead of making my own.
This recipe would be a little more authentic if you skip the canned enchilada sauce and instead made your own. VERY EASY. Take 3-4 large dried ancho chiles (cut off the stems and remove the seeds) and boil them with a cup or so of water, garlic and onion. After a half hour, whir it all together in your blender with a small can of tomato puree. Add some cumin if you like. Salt to taste. I live in Mexico, and believe me, there is NO such thing as canned enchilada sauce here. Also - the shredded or sliced chicken is usually added as a garnish here, not cooked in the soup.