Configure Xchat with Tor

  mapaddress 10.40.40.40 h7gf2ha3hefoj5ls.onion 

and restart Tor. Of course you can use any private ipv4 you want.

Configure SASL authentication for Xchat

Various IRC hidden services need SASL authentication to use it. That means you have to have a registered with NickServ nickname. Whatsmore you need to enable SASL for Xchat.

Configuring SASL for XChat: Perl script

This script is based on the SASL script for irssi, and was ported by Lian Wan Situ.

/sasl set IndymediaTor myNickname myPassword PLAIN
/sasl save.

To see other options available, you can run just /sasl.

Sources