Mario Odyssey, Breath of the Wild, and Splatoon 2 will all pass 10 million

[PAOerfulone]

Splatoon 1 on the Wii U is at 4.8 million as of the end of March.  https://www.nintendo.co.jp/ir/en/finance/software/wiiu.html 
So, it pretty much already hit that 5-6 million mark on the Wii U.
If it does double that amount, than we're looking at 10-12 million for 2 on the Switch.