This video by Brad Menny talks about what we might see there
Never heard of Nintendo Live before his video, basically seems like it's a Nintendo-only E3 held in Japan. It's only 2 days, 10/13 and 10/14, but it looks like New Horizons will be there both days. Found the official site, not much to translate especially on the unclickable pics, but I used Google Translate camera to translate the picture at the bottom, which basically confirms that there will be photo opportunities with Tom Nook. lol.
Yeah, there was some discussion of that on this thread. Unfortunately, the conclusion they seemed to come to was that it's unlikely that there will be any news about the game, especially since the event might be cancelled altogether thanks to a typhoon.