Blake Jorgensen didn't say launch and without a timeline, this could be just about anything. It could be FIFA due to its popularity. EA has released FIFA around September/October for like the past decade so releasing a game within six months of Switch's launch isn't a bad goal. Ideally, any third parties committing to Switch support should be aiming for something new and something soon after if not at launch.
Otherwise, it could be Star Wars Battlefront 2 though that probably won't release until November 2017. Despite what the developers say about current plans, Mass Effect: Andromeda makes the most sense as a launch window title granted its development stays on schedule.
Personally, I just want a new NBA Jam, but I'm just being selfish.