>> Nanny nanny boo boo? LOL! What's that?
http://duckduckgo.com/?q=nanny+nanny+boo+boo&t=vivaldi&ia=web
It was following the 'childrens' mini-meme ...
Children love to say "I know something you don't !"
So, nanny nanny boo boo is a return taunt that children issue. I didn't think it was a 'Southern thang', but some of the sources say it is.
When the children are mad at someone, the taunt is extended with '... stick your face in doo doo'.
I had forgotten about that part until you asked me 'What's that'.

Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good ...