It's been a long time coming, but the Scarlet & Violet nuzlocke is now available on Nuzlocke.app. To be completely transparent there have been challenges with;
Necessary tech upgrades & breaking changes
Data & Image availability to create it
Personal time to push the feature over the edge
But that's not all! With the trend towards Open World Pokémon games, random encounters are getting harder to work into your Nuzlockes. So I've built a new Randomize feature. 
This feature "pre-calculates" all of your encouters (without dupes!) but keeps them hidden until you reach that route. This way, you can keep the randomness of a nuzlocke challenge with the added fun of hunting the Pokémon you've revealed!
To try out this new feature, Create a new Game and hit the Randomize button.