Not the way you phrased the question. A nonresident alien is, by name, not resident in the US. Therefore, "...nonresident aliens in the US..." is a physical impossibility. I think what you may have meant to say is "...nonresident aliens claim tax benefits..." If that is indeed what you meant, then yes, you benefit from a treaty rate on the dividends. The capital gains are already US tax-free without the need for the treaty. You will need an ITIN to gain these benefits. Without an ITIN, they may end up taxing the dividends and the capital gains at 30%.