Place the chicken breasts in the bottom of the slow cooker.
In a small bowl, mix together the buffalo wing sauce, garlic powder, onion powder, black pepper, and salt.
Pour the buffalo sauce mixture evenly over the chicken breasts in the slow cooker.
Add the unsalted butter on top of the chicken and sauce.
Cover and cook on low for 4 hours, or until the chicken is cooked through and tender.
Remove the chicken breasts from the slow cooker and shred them using two forks.
Return the shredded chicken to the slow cooker and stir to combine with the sauce.
Remove about 1/4 cup of the sauce from the slow cooker and mix it with the Greek yogurt in a separate bowl until smooth.
Stir the Greek yogurt mixture back into the shredded chicken in the slow cooker until fully combined.
Sprinkle chopped fresh chives on top before serving.