The problem with a nicklist sort is that EVERYONE will initially seem to have joined at the same time, i.e. when the sorter joins the channel. It therefore relies on the user's client being around 24/7 to monitor all comings and goings.
Depending on your network (? - it works on IRCnet), using /who #channelname will return a list of users, ordered by when they joined the channel (starting with the most recent joiner) - as seen from the server you are connected to. The results can easily be scripted into a format that you can use.
The pitfall with any form of listing is always going to be net splits, which appear to be quits followed by new joins.
Oh, and I almost forgot to mention - /who results also include details such as whether the users are opped or voiced - so could be sorted on receipt prior to display.
Hope this helps
PastMaster