Those are usually all regular notices, so use the on NOTICE event.
To make a cleaner event, add nickserv and all other services and/or users you want forwarded to the user list (alt-r alt-u) making one line for each service in the format
where the first is the same name as below, and the rest is nick!ident@address, you can get this from a /whois nickserv.
Then add this to your remotes (alr-r alt-r)
echo @extra $nick -> $1-
This way you can also get Q,L,X messages from other networks without a log if ($nick == ..) elseif ($nick == ...) chain. Note that one some networks services use server notices, in that case see the help for the on SNOTICE event...