I'm trying to use the following regex to catch this sort of nicks which used by the bot. Could you please help why it's not working.

Quote
on 1:join:#channel: {
if ($nick isop $chan) || ($nick isreg $chan) || ($nick isvoice $chan) { return }
if $regex($nick,/[A-Za-z0-9].+(_){4,10}.+[A-Za-z0-9]/gm) { .gline $nick +5d Bot }
}

Nicks are like
WE_____LOVE_YOU
HIDE____IFYOU_____CAN