Nuts, Like Dalli Resham stated, you can get your visa on arrival. Just have a passport size photo and $30 handy. Make sure you have exact change as those immigration clerks are known to pretend not having change. In my previous experiences, I never had to wait very long for my visa. Just fill out the form before landing and join the line. I don't see any reason for you to carry your Nepali passport or nagarikta with you unless you expect to need them for any other purpose during your stay in Nepal.