I've read that there is a tool called NsdAnalyzer that was available at the Lotusphere 2007 (HND202).
It's suppose to be a Beta version...hope it will be out soon!
On page 42,
In addition, we have a special surprise for you; we have provided an alpha version of NSDAnalyzer (part of a tool called ISEW) for you to use with this lab, a tool used to view and analyze an NSD. This is an internal beta provided as a special courtesy for Lotusphere only. No – we won’t give you a sneak copy to take home with you, so don’t bother asking. . However, we are giving you a preview of a tool that we eventually hope to make available to customers for use in their environment. We do not have an ETA for when this may be available.
I like to read NSD files :-)