Antiochus is O.T. Josephus, and Nero is N.T. Josephus. It has nothing to do with reference and everything to do with chronology. Anyone whose life overlapped or came after the life of Christ is N.T.
As a side-note, Alexander the Great is totally doable without using anything extra-Biblical (although Josephus would probably end up being used to get his actual name in the reference, like the Emperors and Antiocus).