Place the chicken breasts in the slow cooker.
In a bowl, whisk together honey, Dijon mustard, apple cider vinegar, garlic powder, onion powder, salt, and black pepper until well combined.
Pour the honey mustard mixture over the chicken in the slow cooker, ensuring the chicken is well coated.
Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is tender and easily shredded.
Remove the chicken from the slow cooker and shred it using two forks. Return the shredded chicken to the slow cooker and stir to combine with the sauce.
Serve the shredded chicken on sandwich rolls and add any desired toppings.