Sorry, don't know why I didn't see your last reply as an unread message next time I looked.
Anyhow, in the Highlight section, there's dropdown box where you can select message, nickname or both. Select nickname.
Enter the nickname that you want to be matched in the box "Highlight lines that contain these words"
Note: If you want it to match your nick, so that you get a highlight when someone says your nick, you can enter $me into that field.
