If you consider Switch to be a console then it will end up as the 3rd best selling console ever. Behind PS4 and PS2.
If you consider it a handheld first and accept the 118 million Game Boy sales as a whole then again Switch will likely be the 3rd best selling ever. Behind DS and Game Boy.
What is PS4 at 106 million? I think Switch's max potential is 103 million.
Bite my shiny metal Cockpit!