In a large skillet, cook ground chicken and onion together until chicken is done and onion is translucent. Add garlic and cook a couple minutes more.
Transfer chicken mixture to slow cooker and add carrots, celery, sweet potatoes, chili powder, cumin, chicken broth, and tomato sauce. Cover and cook on low 6 - 7 hours or on high 3 - 4 hours.
When done, uncover and stir in buffalo wing sauce, ranch dressing, green onions and cilantro.
Serve with shredded cheddar cheese and extra cilantro and green onions, if desired.