Is the Switch's 3rd Party Support a Major reason why the Switch is selling well?

[Salnax]

On out list of best-selling Switch games, the Top 19 games are all Nintendo productions. So I'm tempted to say no.

That said, we have a handful of third party games with over a million copies confirmed (Mario + Rabbids, Minecraft, Octopath, Skyrim, FIFA, Taiko no Tatsukin), not to mention however many games that we don't have confirmed but can speculate have sold that well (Bomberman, Just Dance, Sonic Forces, Fortnite, etc).

Let's try another indicator: online retailers (at least in the USA). Of the Top 20 skus for Switch games on Gamestop, 5 are third party. From Best Buy, it's also 5 of the Top 20. From Walmart it's 9 of the Top 20, and from Amazon, it's 8 out of the Top 20. Notably, these games are not all the same five titles, though Minecraft is a recurring presence.

I guess overall we can give third parties roughly as much credit on the Switch as we can for the success of the Wii. It's a Nintendo-led success with 3rd party contiributions.