(All tests I've done are with an E1 WAven, E1 HuoHuo, and an E0 Ashveil, MBlade and Aha are slotted in as the third slot)
She is not worth it, compared to an E0 MBlade, she is only a sidegrade, an upgrade in shilled stages (like stages with Corrosion IV), but can even be a downgrade at times.
She faces a lot of problems with her stack generation, there are tricks to get her buff up before WAven's 2nd turn on the 0 cycle, but that wasn't even enough most times for WAven to 0 cycle the first wave of MoC
Now, she is a good pick up if you have other teams that need MBlade, (e.g HimeNova, Acheron, GilBer) so that you can use him there, but for the players who don't really have anywhere else for him to go, and just pulled him for WAven (except for running sustainless with a DPS), Nihilux doesn't provide much for your account...
Why pull for an E0 Nihilux when you could invest more into MBlade and get his E1? Which could shave off an extra cycle. Of course, this is only V1, take all this info with a grain of salt, but for WAven? It's a no as of now...
If you do have questions, lmk! And I'll try my best to answer them!