Wiseman could have traveled back in time before then, depending on whether this moment was before or after the events of Season 2 (since the two points in time seem specifically linked and synchronized). Or it was Chaos projecting in a similar form to Wiseman, one of its previous incarnations.
And I guess it is true if Ganondorf can be born to the Gerudo while being an incarnation of Demise's hatred, and an evil dream demon can die and be reborn to a Titan...
Also of note, Wiseman being from the future and Chaos was temporarily destroyed until, long after Wiseman's death, reincarnating as Sailor Chaos, when did Chaos create Wiseman? Did it reincarnate by the 30th century already and send one more incarnation to threaten the universe? Or did it create Nemesis in the present day, as its incarnation? Could it be that Nemesis was the incarnation of Chaos, and by merging with Nemesis, Wiseman became that incarnation? (Of course he was already pure evil and very powerful even when he was human, maybe he received his powers from Chaos sent into the future from the present day equivalent to the centuries ago from the 30th century?)