Passport ko ta k samasya bhayo ra, nagarikta bhaya ta bhai halyo ni. American passport lay nai badi subidha dincha hola ni. Usually dual citizens have two passports and have to use the one that belongs to the country they are entering. When they travel third countries they can use one of the passports with most benefits to that country, meaning considering visa fees etc. That's how it works for mexican, canadian and other european dual ctzps with USa ctzp. NEPAL might do it differently as it is completely it's discretion.
Some people had sceeen shot of the page in rajpatra where it was listed then i tried to search in that website and found nothing. I have a cold feeling that it might have been taken back due to the court case. I hope not but it's Nepal and there are lots of jealous people.