We had some discussion with Nexcenta quite some time ago, but it never got past that. My take away as an SE was that there is nothing that would keep it from working, but also not a whole lot of benefit at the end of the day, and testing never commenced. In this use case, we had a customer who wanted an NFS solution and there was some thought of using Nexcenta as a gateway like Compellant does. Having worked with Compellant, I was more than a bit skeptical - the NFS implementation is notoriously poor in the eyes of the SEs. Many have sold it once, very few sell it a second time after the first customers reaction.
After some discussion with my counterpart on the Nexcenta side, it really came down to the fact that they don't want to work with a SAN, they are into the host based, horizontally scaled model. In fact , his first words to me were "I hope you aren't planning on using us on a SAN!" Since that was exactly what I was investigating, well, that sort of made for an awkward conversation.
For NFS these days, we HAVE done some testing with Microsoft server 2012 with truly mind blowing performance results, and I have no reservations about recommending that other than the religious discussion of whether Microsoft can do NFS (I've seen it, they can - don't say different until you test it).
Having said all that, what are you trying to accomplish with a Nimble/Nexcenta combination? Aside from file level presentation, most all of the functionality you would get is already in the Nimble array, and the rest really isn't relevant in a SAN.