It's an interesting question of comparison actually. Valve run the world's biggest videogame ecommerce platform, for PCs only (including handheld PCs like steam deck). Nintendo run a comparably large videogame ecommerce platform, but only for their two hardware platforms: switch and switch 2. Just roughly based on hardware sales, seems to be roundabout the same audience size. Nintendo maybe comes ahead because they're well established in the hardware space (Valve is trying to close the distance), and of course far, far away in terms of 1st party game development - Valve has, what, 8 games? All phenomenal, but nothing compared to Nintendo's library.
Does Valve even make games anymore? The only thing of note they've done since like 2020 is put a fresh coat of paint on CounterStrike. Which still counts of course but it feels like they are REALLY coasting on the reputation of games that came out 20+ years ago.
Valve's working on Deadlock, an FPS / MOBA. It's very polished, but in early access right now. Based on what I've seen when I tried playing it, and just what I hear in the gaming sphere, it'll probably be a decade-defining multiplayer game once it's done, like TF2 or CSGO both are.
They definitely coast, but when they do release something, it's always phenomenal. I do wish they'd make more games, though.
Valve are the 200kg gorilla of the gaming industry and can throw their weight around.
However Nintendo are a 250kg gorilla.