At the launch of Nintendo Switch Online, software updates will be made available for several popular games to provide support for voice chat via the app, including:
DRAGON QUEST BUILDERS 2
Mario Kart 8 Deluxe
Mario Tennis Aces
MARVEL ULTIMATE ALLIANCE 3: The Black Order
Super Mario Party
Super Smash Bros. Ultimate
Plus, the entire NES - Nintendo Switch Online game library will support voice chat using the Nintendo Switch Online app.
For additional information, please see the full list of compatible games.