I'm simply pointing out how hypocritical people are on here. All season I've heard homers from other teams bash Nico's lack of production and go on about how X player will be better than Hischier...
I completely understand that Nico wasn't a sexy 1OA pick. Hell, I wanted Patrick and I'm eating crow right now (although I think Patrick will still be a fine player, I just think Nico has far more upside). But he literally just put up an excelling D+1 season, outperforming pretty much everyone's expectations, and there's no reason to think he'll stop progressing. Do I expect him to be a top 5C in the league? No, I don't, but I also don't expect him to top out as a RNH/Duchene type.
Now to go to the OP's question, Nico has a lot of potential. Will he progress linearly? Probably not (if he continues to progress at this pace he could become a top 5 C, but it's very unlikely that happens). But to say he'll stop progressing is flat out asinine (It's more likely that he progresses dramatically than that he plateaus and stops progressing). He's not physically mature yet and progressed throughout the season. He also played through an injury. This is also only his second season in NA and a far more intense schedule than anything he's experienced previously. All that means I think he has a great shot of being a top 10-15C in the league.