Prepare the slow cooker by coating it with a light coating of cooking spray.
Place the onion, garlic, peppers, and celery in a microwave-safe bowl, cover, and microwave for 4–5 minutes to sweat the vegetables.
Place the chicken breasts in the bottom of the slow cooker and season lightly with salt and pepper.
Surround the chicken with the microwaved vegetables.
Add the beans over the top, then sprinkle in the chili powder, garlic powder, and onion powder.
Pour the buffalo sauce and chicken broth evenly over the ingredients.
Cover and cook on Low for 6–7 hours or High for 3–4 hours, until the chicken is tender.
Remove the chicken, shred it with two forks, and set aside.
Scoop out about 1 cup of the broth and 1 cup of beans, place them in a blender with the cream cheese, and blend until smooth.
Stir the cream cheese mixture back into the slow cooker until creamy.
Return the shredded chicken to the pot, stir, and cook for an additional 10 minutes before serving.
Garnish with parsley if desired and serve hot.