Mount Everest it is as simple as this. First Nepali is a language of khas people (bahuns and chettris) and so identifying any other group as Nepali would be wrong (which is the reason for identity crisis in Nepal these days). Second Nepalese describes people of Nepal and does not choose any particular group to identify with and Americans know this so they call us Nepalese and not Nepali. So next time someone asks you what is your nationality? You let them know you are from Nepal and are Nepalese and then if you would like to identify youself with your ethnic groups then go on to explain that as well.