MAME has NUON files probably stub

[WhiteMagicRaven]

Keep eye maybe there something can be useful?
mamedev/mame@ad19f90

[toxieainc]

In principal yes, i also follow it already.

For now there is more or less nothing though. Also note that MAME follows a different principal: Emulation should always be as exact as possible, whereas Nuance focuses on making the games playable in practice. This means MAME emulation will be much much slower when it arrives at some point (which is perfectly fine, as the team there focuses on accurate preservation).
You could for example compare this to something like https://github.com/trzy/Supermodel/ for Model3 HW. It takes some shortcuts and also doesn't want to be cycle accurate. But this makes it far more playable compared to the emu in MAME.