If you or a bot are always in the channel, then you could put something like this in the remotes.
Code:
on *:JOIN*: {
if (Anon* iswm $nick) {
.notice $nick Please change your nick within 2 minutes, or you will be kicked.
.timernick 1 120 kick $nick Please change your nick
}
}


I realize that's a pretty basic way to handle it. You could build in a counter for if the person has been kicked once so you could ban them if they don't change their nick the second time, although that might not be practical to hold all the variables for counting people.

Bears on Patrol Chat