There is definitely a GTA audience on Nintendo consoles, it's just much smaller than on other consoles. The trick would be to bring GTA fans onto a Nintendo platform, which might be done by a solid standalone spinoff (in addition to a port of GTA V). I'm not sure that Rockstar has that kind of interest in expanding into Nintendo territory.
That would be good for Nintendo but not for Rockstar. Why would they want to make an NX game to have the same audience they already have on other platforms? Thta would not benefit them in any way.