Place the chicken breasts in the bottom of the slow cooker.
Add the beans, crushed tomatoes, onion, garlic, celery, chicken broth, Buffalo sauce, chili powder, cumin, salt, and pepper.
Stir gently to combine the ingredients without breaking up the chicken.
Cover and cook on low for 6–7 hours or high for 3–4 hours, until the chicken is tender and fully cooked.
Remove the chicken from the slow cooker and shred it using two forks.
Return the shredded chicken to the slow cooker and stir well.
If using cream cheese, add it now and stir until fully melted and incorporated.
Taste and adjust seasoning or Buffalo sauce as needed.
Let the chili rest for 10–15 minutes before serving for best flavor.