If you don’t want to work while studying. Coming to US as an undergraduate student will not be a good option for you. Very very few universities will waive your tuition. If you have a good I. Sc try to get same in you undergraduate studies in Nepal and come for graduate studies. If you have a good GRE score and good scores you will definitely get a Graduate Assistantship and stipend that will be enough to survive in US without working outside. That’s what I have experienced.