N.C. symbol?

[Tim McNamara]

I need to be able to put a symbol for "no chord" (such as N.C.) on  
several lead sheets and can't find a simple way to do it.  Or,  
really, any way which I find even remotely comprehensible.  It seems  
like it ought to be possible- and that the simplest way would be- to  
put something like:

  a2:m7 d2:7.9-
  g2:m7 c2:7
  nc1

into the chart using \chordmode and get a nice fat N.C. among the  
rest of the chords.  Is there a way to define this in a .ly file to  
be \included into the chart?  That sort of thing is beyond my  
knowledge and I didn't find anything in the LSR or the documentation  
thus far.

Thanks!