I agree with Kaji. You got to have a fairly good confidence on your family's potential reaction. If you have a gross doubt on that and mainly if you value your family's decision overrules yours, chances are you are not going to be happy. Don't mean to discourage you, though.

In our culture....they say something to the effect that 'a marriage is not just btn a boy and girl, it is btn a whole village to an another whole village'. If you believe in that you are better off with a Nepalese girl. Not to set the negative tone, but there are other important human sides (the traditional/cultural ones)  you may value more that only a Nepalese girl may fulfill.

But if you believe that you truly love this girl, and believe that YOU are the ONLY one to face the married life for a better or worse regardless of your wife's ethnicity, and believe that you two are well compatible to each other; it's the end of discussion. Your family loves you and they want you to be happy. 

I don't know your family background; mainly how open are conservative they are..('gaunko manchhe' don't necessarily make the conservative ones, I have seen super narrow minds in very well educated  and well-to-do families). If they have seen some precedence, they may be ok. If they are conservative, believe me the chances are even your Nepalese wife may not fit  in if lived together for more than a year or so. (Just visiting for 4wks in 2yrs might work.)

I know its a tough decision, I hope you will be able to sort it out. 
Good luck, brother.