Not directly. However, we do know that the sword Szeth recieved is an Awakened Sword Commanded to "destroy evil," (the same Command Nightblood was Awakened with), Brandon has obliquely alluded to the Ardent Zahel being Vasher (which is also alluded to by the book), and the last person we know of who possesed Nightblood was Vasher... There isn't muchin the way of a concrete confirmation, but the logical conclusion is that Szeth has Nightblood.
Thank you, very much for watching for and correcting grammar and spelling. It helps greatly to the quality of our wikia. Also sorry for making your life hard with my english, I try to keep to the templates, but sometimes my inclusionist nature get the better of me ;)