Well, assuming that Nimoy's involvement is in a 'bookend' to the story, I'm guessing it will be set in the late 24th century, as it wouldn't make a lot of sense to have Spock appear older than he did in the TNG ep 'Unification'.
That's my guess, but I guess the bookend could be set a decade or so after Kirk's disappearance on the E-B.
That's my guess, but I guess the bookend could be set a decade or so after Kirk's disappearance on the E-B.