User blog comment:IHHeroes/Changes going forward after Crisis/@comment-43707041-20200116194029/@comment-2054358-20200116235704

That'll be the only way to justify Harrison Nash Wells' existence on Earth-Prime. If Eobard Thawn never killed and replace Wells, everything would be a lot more different from this, so Nash has to be from another universe and probably had no idea what he was doing there until J'onn woke his memories.