Nylander's got the potential to be a point per game player, but not how he's currently playing. He's too much of a perimeter guy now and doesn't play enough in the dirty areas where a lot more points are produced.
The big difference between a guy like Marner and a guy like Nylander is Marner seems willing to go anywhere on the ice to make a play, whereas Nylander seems to only look to create if it doesn't involve him possibly taking a hit or having to battle toward the net.
*Key word "consistently" since this forum has a tendency to want to nitpick minute details by showing a video of one or two times where Nylander scores/assists on a goal 5 feet from the net in the dirty areas.