I don't know if either is a "build around" type player, don't think that either will be the best player on a contender level team in their careers but both should be nice core complimentary players
I'll go Nylander but they're very close. Aho had 40 seconds more pp time per game, a little more ES time per game and a shooting % that was above his career average (not out of range of what could be sustainable, will have to see where he levels out to as a norm), Nylander had better linemates (though I think it gets forgotten than he and Matthews drag Hyman around, the linemate situation is only half good) and an OIsh% that was probably higher than what you'd expect to continue. I think that this will look like Nylander in the near future because of the context he'll be playing in with a high powered offense that will stretch matchups thin with it's depth, so I think the production spikes
Aho for pick value for sure, he's a home run for the Canes