I disagree. I don't think that Nihilus and the Exile are alike. Nihilus feeds from force sensitives to sustain what's left of his soul. The Exile merely bonds with them, he's not necessarily feeding off them for survival, but for power.
Plus, Nihilus's victims become mindless slaves. Though Exile does affect their judgement, I still think all of the people he bonded with were rational.
And if Nihilus was a part of the Exile, wouldn't the Exile have died, when he perished? He wanted the Exile for his ability. Nihilus needed to feed from force sensitives, and I think he wanted the ability to bond with them better, to further sustain him and make him stronger.