Decided to go ahead and make a spreadsheet of all the first party Nintendo games that have exceeded 10 million units (as of the most recent sales update).
There are 52 first party Nintendo games that have exceeded 10 million units (and I expect that number to continue to rise with Switch over the next few years. The Switch has the most 10 million sellers, but Wii's 10 million sellers have actually sold the most (thanks to Wii Sports being bundled), but I do expect Switch to overtake possibly as early as the end of next year.
As expected, neither GameCube nor Wii U had any 10 million sellers on the list, which also means that none of their games are in the Top 50. Also, 10 games on the list have exceeded 30 million sales and almost half of the 10 million sellers have exceeded 20 million. Of the games on the list, N64 has the smallest presence with just 1 game (MK64 narrowly missed the list).
The total sales of all the games on the list exceeds 1 billion! How many 10 million sellers do you think will there be in total at the end of Switch's life? (Feel free to include games that haven't been announced yet in your guess, such as Gen 9 Pokemon.)