One notable trend with the Switch that has emerged is that software sales for Nintendo's own games are the best they've ever been. Not only are mainstays like Mario, Zelda, and Smash Bros. breaking series records. But ports are regularly outperforming their Wii U counterparts, and even niche oddball stuff like ARMS and Astral Chain are able to pull a solid 1-2 million copies.
What about the Switch is making Nintendo's software soar in sales? My take is simply, how the Switch presents itself. The Switch is designed to be a device meant for games before anything else, aimed at anybody and everybody who plays games. Regardless of what you want, there's at least something about the Switch anybody can gravitate towards. Unlike the Wii, which was pegged with a "Casual" stigma that it was never able to fully shake. The Switch works well for both novice and dedicated gamers, and thus games of all kinds are able to find a home on it.
I honestly think software sales this strong is also what allows Nintendo to take more risks with their games. When even something as odd and Japanese as Astral Chain can debut at No. 1 on the UK charts, what do have to loose? Sometimes people think that less success means companies take more risks as that means they need to find something that might stick. But I find this to be untrue a lot of the time as it only really applies to companies who never really had many hits in the first place. In cases like Nintendo, its the opposite. You can see this as recent as the Wii U, where Nintendo began doubling down on established franchises because software and hardware sales were underwhelming. Or in an non-Nintendo case, Sega, who announced recently that they'd be focusing primarily on its established core franchises going forward due to poor software sales. Point is, when your making a lot of money on the best software sales you had in years, might as well spend some of that war chest on weird shit too.