Hapkido is essentially aikido mixed with TKD. Chin-na is an aspect of fist fighting that employs grabs. Chin-na is not always a joint lock it could be grabbing a muscle, like on the neck or arm or it could involve a "press" which is a kind of strike that is supposed to "seal" or cut off the Chi energy.
One major difference between the two is that aikido/Hapkido has a heavy dependence on blending forces with the opponent. Where as Chin-na is merely reaching out and grabbing the other guy in a painful manner.
Chin Na (Qinna) is a subset of many different CMA's. Some people teach it as a seperate art when talking about it, but it was just one aspect of the whole art. Kind of like "Dim Mak", some people teach it as something seperate, but it used to be a small part of the whole art.
So, in an of itself if you removed all of the punching/kicking aspects of Hapkido and were only teaching the joint locking techniques pulled from the art than you would have the Korean equivalent of Chin Na.