Place chicken breasts in the bottom of a slow cooker. Top with chili powder, salt and pepper, and minced garlic. Add red onion, diced jalapeno and frozen corn, then add the four cups of chicken broth.
Cook on low for 4 hours, or until chicken is cooked through. Remove the chicken from the soup and shred, then return to the slow cooker. Add cilantro, heavy cream, cotija cheese, lime juice and stir. Let it cook for another 15-30 minutes, until everything is heated through.
Serve with additional cotija cheese, diced jalapenos, and a drizzle of mexican crema or sour cream (if desired).
Notes
If your soup is to thin you could use an immersion blender to cream some of the corn and thicken it up. If you want to add even more texture, you could also stir in some sour cream.