well before you all gang up on me, let me make some points here. 
1) NRN = non resident Nepalis , not Americans who were never a Nepali. I am talking about someone who was born and raised in Nepal and during his life time end up getting citizenship from other country. Technically Nepal defines everyone as NRN who has lived more than 18 months or so away from Nepal, including F1 students in the USA. How Americans invest , and how it is feasible becuse of their giant foreign policy is outside the scope of this thread. and yes, America does allow dual citizenship. 

2) If anyone wants to sell their property they can always sell it when they are in green card for 5 years, h1 for however many months. You can still go to Nepal and sell your property. How in the Hell does "maal" finds out you have an American passport, or you can have it transfered to your sister, brother , nephew , niece , mother , wife and sell it. thats is not the point , one can always sell their property. Point is if you make Nepalis who live outside feel like they can't invest in Nepal or let's not even say invest even retain their property securely then they won't.