I didn't like it. I felt Nimoy should have bowed out as he did the 2009 film. It was a nice passing of the torch that it should have been left alone. Dredging him back for STID felt like fan pandering than anything else. If you had cut that scene out you wouldn't miss anything. Spock Prime only tells nuSpock things he's already aware of (Khan is really really dangerous, watch out for him).
It's such an unnecessary moment that it would be a shame if this was the last time Nimoy was ever brought in as Spock. At the same time, I would be hesitant to even bring him back again just to give him a final proper send off because I really want this new cast to make the films their own without having any call backs to the original series.