Who would win?

would cause when there's DARKNESS there's no shadows and relies on shadows

Nocturne , as he can E as soon as Zed ultis blocking death mark. He has CC while zed has none. He is better duelist. He has sustain from his passive. Now if u ask lore wise, there are some theories that Zed and Nocturne are same person and that Nocturne is actually darkness inside Zed that corrupted him. In any way Nocturne wins.