Yes. There is a glaring issue with the fact that the Nika Fruit has not revealed itself to the World Government. However, that increases the chances it was actually among pirates waiting for Luffy to find it.
I feel like Heaven decides a lot of things in this story, and it has decided Luffy would use the Nika Fruit, but what if things were slightly different?
If Xebec had gotten his way, nothing is off limits (not even the Nika Fruit). We probably won't get a Dark Nika unless somebody pulls him out of a dream or something, so Xebec trying to become one is about the closest I think we'll see (unless we see a flashback of Nika in a dark form during one of the previous worlds).
It would be hard to argue anyone achieving it for any reason, but Luffy and Blackbeard and Roger and Xebec seem tied to the Ancient Kingdom values and I think that could have justified his use of it. If Luffy is the Light side of the Ancient Kingdom and Blackbeard is the Dark, then the Nika Fruit, if the Heavens were favoring the Ancient Kingdom with that fruit, then either of them could get it.
The Heavens would be justified in this because Vegapunk said he couldn't judge who was right or wrong in the conflicts during the Void Century. What he didn't say was that the Ancient Kingdom's beliefs and values were advanced and simple people wouldn't be able to decide that. In other words, both Light and Dark Nika may appear as a result of the Heavens deciding it. If Luffy appeared as Nika because of that, then if the Heavens decided it, Xebec could have done it too.
Just think of it as a "What if" justified by parallels with Roger/Xebec and Luffy/Blackbeard.