I would check in the car specific forum as they would have more of an idea but as its a newish car i'd guess it is 100% in the ecu so either a bypass chip or something to turn it off in the ecu would be needed. In my current daily car it was a simple process of removing a tiny little board from the ecu casing, it was literally just cut two wires to get rid of it.
zeroforum?id=176 is the forum linky. I'd ask there.
Going by past nissan ECU's it should be easy to program, might even be as simple as loading up some software and unchecking a box. I think there is also an impul ecu upgrade that I would assume would get rid of the speed limiter.