This is Stone. He's a veritable master, and I'm not sure there's anybody else even in his tier.
People are just going to name defensive forwards but that doesn't mean they are the best. For example, Nylander has one of the most effective poke checks in the league (especially in the Neutral zone) but I don't think anyone will call him a defensive specialist or even good defensively.
Man your point went over some heads there. I like how you say that nobody would call him even good defensively, and get accused of claiming he's good defensively.
Anyway, for those that wonder where this is coming from, I'm guessing it's based on his takeaway rate and stats published by The Point. They have access to a lot of stuff that aren't publicly available, and they had Nylander actually leading all forwards in the league the season before last in 'Defensive plays in the neutral zone'. I don't remember quite what was included but from what I remember it was pretty much anything the player actively did to halt a puck carrier's attempt to generate transition and/or offense. I'd venture that in his case, most of that comes from funneling players into areas where they trapped, which he does very well, but he's also very good at disrupting play with his stick checks.