glad to hear the dry-it-in-rice trick helped you revive your iPod touch.
from the symptoms, my first guess would be the battery is damaged and needs to be replaced, do you have access to a voltmeter to check its voltage when charging/fully charged? I guess it's also possible there's still water inside the battery or elsewhere causing trouble - it can take a long time for electronics to dry out...
It could also be the charging circuit, but without a known good battery it may be difficult to confirm. perhaps replacing the battery first is a relatively inexpensive first step. Good luck