It's hard to say what should happen in the future.  This story is 
obviously a branching from the origional, but are you setting it before or after 
Ranma became Nabiki's fiance?  If before, will you arange a similar situation 
except with Nabiki wanting to keep Ranma instead of get him and Akane to pay her 
for switching the engagement back?  If after, will we have any moments when 
Nabiki thinks back and feels sorry for not trying to make it work that time?
	Anyways as for the outcome of a Ranma Nabiki match up, It's up to you.  
Now Ranma and Akane being in love is one of the foundations of Ranma, changing 
this is thus a greater departure from the norm than anything else.  Which simply 
means it'll be a bit more of a challenge.
	Still the real question is how Nabiki will be acting now.  Ranma has an 
extremely strong sense of honor (Probably to make up for Genma's lack of one)  
Whereas Nabiki has always been willing to do a lot of underhanded things for 
money.  Will her love for Ranma inspire her to change this?  (If they wind up 
together it had better be because of something other than a scheme).