Can I link my Nintendo Account to more than one Nintendo Switch console?
You can link your Nintendo Account to multiple consoles. You can play digital games you've purchased on any Nintendo Switch console that has been linked to your Nintendo Account. Please note that you can register one primary console per Nintendo Account.
Once you've registered a primary console, your digital purchases can be played by anyone that uses the primary console. Other players will not be able to access your digital games on a non-primary console.
But see the following link, which suggests it is possible:
KotakuSince last week’s release of the portable-only Switch Lite, I’ve been trying to set up my account on both the Lite and my original Switch so my wife and kids can play games like Super Mario Odyssey and Yoshi’s Crafted World on one without erasing my save data or interrupting my playing Puzzle Quest on the other. Nintendo hasn’t made this easy. Here’s how we’ve made it work.
https://kotaku.com/if-you-have-two-switches-here-s-how-to-share-download-1838438317