Cover the slow cooker with the lid and cook on LOW for 4 to 6 hours, or on HIGH for 2 1/2 to 3 1/2 hours, until the chicken is cooked through and easily shreds with a fork.
Once cooked, gently shred or slice the chicken right in the slow cooker, stirring it into the cranberry-onion sauce so everything is well coated.
Taste and adjust the seasoning if needed (the onion soup mix is salty, so you may not need extra salt), then serve the chicken hot with plenty of sauce spooned over your chosen side.
