The Nuzlocke Challenge has become increasingly popular for Pokémon fans as it puts a new and exciting spin on the games. Its rules make the games harder, really testing players' Pokémon knowledge and skills while adding a fun way to replay titles. It's such a well-known and beloved challenge that there are loads of videos on it, and it even has its own subreddit. This popularity combined with its well-established rules seems like a perfect fit for a Pokémon spin-off offering something challenging to veteran players. It wouldn't be the first time Pokémon has gone roguelike either, considering the Mystery Dungeon spinoff series.
Pokémon's Nuzlocke Challenge puts restrictive rules on a game to make it harder by forcing players to use Pokémon and team combinations they wouldn't normally choose, all with only one life. There are a number of optional rules to make a Nuzlocke easier or harder, but the three core ones are these: the player may only catch the first wild Pokémon encountered in an area, when a Pokémon faints it must be released or stored in a box permanently and all Pokémon must be nicknamed. There is also a widely regarded fourth rule of "permadeath" where a black/white-out means starting over.
Some players like to make the Challenge even more difficult, or fun depending on how a run goes, by using a randomizer. A randomizer varies parts of a game, which can make it feel renewed and just as wondrous as when it was first played. A Pokémon randomizer means wild encounters, starters and even trades and trainer Pokémon can be completely randomized, so players won't know what's around the corner. It adds another level of challenge to Nuzlocke runs as anything can happen and players can end up with a wild team at any point in the game. This version of a Nuzlocke challenge also has a lot in common with a certain subgenre of games.
Roguelikes tend to follow the same basic rules as a randomized Nuzlocke with the exception of nicknaming Pokémon, and it's why an official Nuzlocke game could work. They have permadeath or progression challenges, randomized pathways or content and turn-based combat, depending on the use of the definition. In the case of a Pokémon Nuzlocke Challenge, it checks all three of these boxes. With some changes to the usual formula, a roguelike Pokémon can easily be an official Nuzlocke title. While the overall goal of the game can remain the same, fighting Gyms or doing challenges to become the best, the journey could absolutely be randomized and add permadeath.
Other elements of the subgenre could be added, like procedurally generated routes or caves, to add a new level of challenge besides just randomizing the Pokémon. Even the Gym types could be changed up each run while adjusting trainer and Leader levels to an average for the section of the game they've encountered. An official Pokémon Nuzlocke game could be a great new challenge for veteran players and those just looking for something new in their Pokémon games.