Add the chicken breasts to a slow cooker. In a bowl, mix the cumin, coriander, oregano, paprika, red pepper flakes and some salt and pepper, then sprinkle over the chicken. Add the beans, celery, garlic, canned chiles, onions, bell peppers and jalapeno. Pour in the chicken broth, put the lid on and cook on low until the beans are cooked, the vegetables are soft and the flavors are combined, about 7 1/2 hours.
Mix the milk with the masa and add to the slow cooker. Add the frozen corn straight from the freezer and continue to cook until the sauce has thickened, another 30 minutes.
Remove the chicken to a board and shred using 2 forks. Return to the slow cooker, then add the lime juice, sprinkle over the Monterey Jack cheese and stir to melt.
To serve: Ladle the chili into bowls and garnish with a dollop of sour cream, extra cheese and cilantro. Roll up warm corn tortillas and serve on the side of the bowl.