Hardware:
Switch - 23.25 million
3DS - 73.10 million

Software - Switch:
Super Mario Odyssey - 13.5 million
Mario Kart 8 Deluxe - 11.75 million
Breath of the Wild - 10.8 million
Splatoon 2 - 7.5 million
1-2-Switch - 2.59 million
Kirby Star Allies - 2.9 million
ARMS - 2.45 million
Mario Tennis Aces - 2.25 million
DKC: Tropical Freeze - 1.60 million
Xenoblade Chronicles 2 - 1.5 million