I don't think they have a center in nepal to take Nclex. However, that's true that you have to get eligibility letter from boards of nursing from states here. Length of the process depends on which state you want to go with. I would suggest you to go with California Board of Registered Nursing if you have Bachelor in Nursing. If you have PCL only, than go with New Mexico. Download forms from their website and go through each and every lines. Follow the instructions. There is no stress free way to get through the Nclex RN test specially when you are in another country. Still what you can do is try to make it your best. Good luck!