If you have valid documentation (H1b, F1, or similar) to prove your rightful stay in US. I do not think its difficult to get visa from Nepal. Accidentally people loose their document, and we/you are not exception. If your stay in US was rightful/lawful/legal in the past, and your presence in the future is for a valid specific reason, I do not think you will suffer. Optimism leads to peacefulness.