question will be mainly from your story...
read your story and try to make as many questions from your story.
its good to use hand gestures while explaining your story.
dont hesiate to stand up and act the story out to the officer..
memorize the story as it happened in your story.
memorize  dates, spouse's birthday..kids birthday...etc.
be open and cool.

i hope you are using newspaper stories about maobadi in nepal. along with that try to include US Government reports about Nepali situations. Oficial Reports from UN, Reports from UN humanrights commission, CIA website reports and any other reports from such or organization will be very helpful. i suggest you to hand out these reports at the interview.

good luck !