I do believe Tonightmares was very well done from the videos I've seen, and it was a great way for the HHN team to branch out, but I don't think there's any chance we'll ever see it appear at the event proper. Besides the IP not being a strong draw for a Halloween event, the maze itself was designed specifically to stand on its own as one long experience that's uniquely tailored for the New York area. While Fallon is present throughout the whole experience with his narration, most of the scenes are just various classic Halloween archetypes that are lightly themed to the IP. As is, I don't think the maze would work at Horror Nights without a significant overhaul, but I wouldn't be surprised if it returns to New York next year.