So, if you look on the right, hopefully, you should see some new webchat links. The first one is the the default link as normal, and you pick your nick before connecting and autojoining. The other two however both autoconnect first, and join you to the channel with a random nick (MoF0-somerandomnumbers). If you use either of those, just change your nick with the command:
/nick (nick goes here)
And you'll be good to go.