I'd give my left tit for a fic where a future version of Nile travels back in time and endows the team with their immortality. Go hard with the sci-fi or make it as hand-wavey as you want; I would just love a stable time loop where Nile is the reason why everyone had the chance to meet. Bonus points for her actually interacting with the younger versions of the team and one of them (maybe Booker?) vaguely remembering her.