My spouse is also in the U.S. and works or receives income too. Does he or she have to file a separate tax return or can I just add both of our incomes together and file one tax return?

Nonresident Aliens are not allowed to claim a joint tax return. As such, EACH Nonresident Alien who receives ANY income from U.S. sources must file an income tax return. Therefore, if you have a spouse who works and/or receives any income, he or she must file an income tax return that is separate from you – you may not combine your income on one tax return.