Okay! So, here's a list of potential Worlds that Nick's going to travel to, as well as any Another Riders he may face against. The potential locations are:
The World of Pokémon (battle against Another Gotchard)
The World of Honkai Star Rail (battle against Another Den-O)
The World of K-Pop Demon Hunters (battle against Another Revi and Another Vice)
The World of Zenless Zone Zero (battle against Another Zero-One, and Ethereals, obviously)
World of Glitch Techs (battle against Another Ex-Aid, and Glitches, maybe)
World of Once Human
World of Kamen Rider Legend (not by choice. Nick will basically go through the same thing as Houtaro/Kamen Rider Gotchard when he got pulled into the World of Legend)
Feel free to suggest other Worlds that Nick could travel to in his journey across the Multiverse, and if he should fight an Another Rider. Each world Nick will go to will be one chapter long, unless it's the world he decides to make his new home.