Nintendo seems to be implementing user reviews onto the Nintendo Switch eShop. According to eagle-eyed Reddit user, phantomlinger, Nintendo has pushed out user reviews for some of the games that they published, like Dragon Quest Builders.
To qualify to write a user review, players must have purchased the game and played at least 2 hours of it. This is to ensure that only legitimate reviews are given.
If you look on a page for a Nintendo game, it shows a rating out of 5 stars like used to be on the Wii U.
Closer to the bottom of the page, there is a button to “Review this Game” with text underneath reading
All reviews are from verified players. Nintendo does not endorse any reviews on this site.
Trying to click the button checks your account seemingly to see if you have played the game and if you have not played at least 2 hours, you are unable to review it.
It is unknown when Nintendo will fully roll out the user review system, but at least for now, you can check out user reviews for Nintendo published games.