Usually you find that a message from Nickserv, is but not always a NOTICE.. as with this case from the look..
On *:Notice:*NickServ IDENTIFY*:?:{
if ($nick == Nickserv) { identify yourpass }
}
Also, although NickServ requests you to use /msg Nickserv, if the network supports it, just use /identify.
Eamonn.