All Nintendo First Party 10 Million Sellers (as of December 31, 2023) (+Poll) UPDATED WITH LISTS BY RELEASE YEAR & CONSOLE

[Zippy6]

Upcoming 10m sellers:
Diamond & Pearl Remakes
Pokemon Legends Arceus
Splatoon 3
BOTW 2
Mario Party Superstars

So should get to at least 57 just with games already announced. Not sure what comes after that before the Switch's end, but I'm going to say 60.