User blog comment:Tails365/Nashor VS Lich Bane/@comment-1480791-20140307114330

Lich Bane's damage is instant and those who use LB tend to have skills that proc it so they don't have to AA to get it off. To get the same damage as LB, you have to do 5 AA with Nashor's Tooth. Most AP assassins would've died after 2 AA in a teamfight (most of them won't even land one).

NT probably only works with AP champs that act almost like an ADC, i.e. Kayle, Teemo since their AAs are enhanced and most of their damage come from AAs. But on other champs, I don't think NT works at all. I don't think NT would work for Diana, since she probably won't have the chance to land 5 AAs in a teamfight situation. I've tried, didn't work.