Hi, unfortunately Rizon doesn't support lightIRC due to the necessary flash policy daemon.

An alternative to mibbit is our qchat instance running here: http://qchat.rizon.net. If you click on the icon on the top left of the qchat page, you'll see an option to embed it into your site.

Mibbit and qchat are really the only two truly good options, because they pass the true IP of the user to our servers, compared to other widgets which will serve as an open proxy for users, and be abused and likely banned as a result.