Sure. People have been asking Big Nintendo to put games on PC since [checks notes] Super Mario Special, for two computers which were kind of underpowered and were weaker than the Famicom. Or the attempt from Dangerous Dave in Copyright Infringement.

But yeah, I guess owning the worlds largest individual media franchise that prints money even when said release is the sick of a dog, poor Nintendo missing out on that nice PC money, right?

Really fascinating talk on the business school talk, but the real question remains. OP, could you show us which sites and steps to get Nintendo games to show up on GOG?

If i could still buy a DS i would get it no problem, thing is that its not available anymore, what if i want to play DS games?
I went on the launcher, to see what games were available, so i searched for retro games i liked, i bought rayman 2 and added mario 64 DS to my account, i find both in my library, both are "owned games" tho one is totally not available
Sure Nintendo is rich with their games that they sell on their new consoles, but they could be RICHER, they dont sell their own old games, why not? at least on their most recent console?

Very true! Good thing is: you don't need it to play the games you can purchase here.

Nintendo games on PC... only ones i can think of are Mario is Missing, and Mario Teaches Typing.... Neither of which i expect to be on here.

https://www.mobygames.com/game/3914/mario-teaches-typing
https://www.mobygames.com/game/7106/mario-is-missing

Ok, let's get rid of this myth right away: of course you can still buy a NDS.

Maybe not on the first market anymore, but the second hand market definitely has them in spades.
https://www.ebay.fr/sch/i.html?_from=R40&_nkw=Nintendo+DS&_sacat=0

Same goes for 3DS and 2DS, btw.
And both systems are backward compatible to the NDS.

I bought a 3DS XL off of Ebay last year for around $100. It's a great little handheld, and well worth it, to be able to play the games as intended, with the dual screen and 3D image, on the go. Also, it's not super-old, so the games currently aren't too pricey (unlike many DS and GBA games ...).

I've been playing through Majora's Mask 3D recently - great fun! :-)