The story behind nNn, as I best recall it:

Long ago, when I was just developing my icb habit, there was a spate of booting. (You know, it's lots of fun to suddenly boot everyone from your large group.) One day, as a defensive move, I started forming nicks as long strings of o's, O's and 0's (you try typing "/boot oOo0oOOo0o00" before I can type "/name Oo0oo00oOooO". I hope you don't know how to do cut-and-paste!). Once the boot wars died down, I settled on "oOo" as a nick with nice symmetry. Later, I switched to "mMm", and finally "nNn". That's just where I was when my messing-with-nicks phase ended!