First type your question on the message board. and 2 yrs bachelor are not recognized here, and if you try to join master, they will do credit evaluation and off course they will put you in 200 or 300 level course, and according to the world education board , any science course are not transferable if it is 5 or 6 years old. No math subject are transferable if it is 10 years old. So my suggestion, try you best to do the credit evaluation and then only you can figure out from where u will have to start.

But for sure, you can't join master straight, because, american education system requires many general subject which nepal's education do not teach. so you obviously must take those classes which they teach in community college or any university in ungraduate level.