I don't think 'dual citizenship' in Nepal has taken effect yet.  I guess it will take a few more years.  Like Samasara ji and Yekloyatri ji mentioned above, having a US citizenship has more benefits/priviledges than having PR. Since dual citizenship has not taken effect yet now;  if you go for the US citizenship, you may face some legal complication(s) on your property in Nepal, if you still own one. It is just a thought.