I'm not going to quibble about the logical problems with this idea 
except to say that it's funny enough that I generally don't care.  
This deserves to be developed into a whole story.  Not a series, just
a story.  

If you did do it as a series though, there's no doubt that even if 
Nabiki could be deported for marrying an illegal alien (and she can't)
she'd likely set up shop in Hong Kong rather than going all the way back
to the valley of Jyusenkyo.