Vitamins, soda, massage, battling, I believe Chansey can be taken for a walk in Amityville Square...
...but Soothe Bell is the best bet if you're not training for battle. Just wait until you're breeding and whilst you're hatching up by Solaceon, have a soothed Chansey in your team.
If you are training, save time on EV training with a bunch of vitamins. A full flying start will make him evolution-ready.