First update includes fixes for using Discord in game mode:
Patching Proton for Discord: created a patch to allow for Discord to be used in Game Mode. All you need to do is hit the “Update Proton GE” button and NonSteamLaunchers will apply the patch for the current proton GE. This will allow Discord (Native Linux) to be able to be used in Game Mode, so you can finally stream the video and audio and capture your game to your friends. This will automatically work for all of your NSL Games.
SteamDeckHQ has an article on that here.
Second update added playtime trackers for non-steam games in game mode.
Playtime: Playtime has been implimented into NSL for all non-steam apps in your library. This will only show in game mode for now, even for Desktop Version peeps that use NonSteamLaunchers. All you have to is run the NonSteamLaunchers.desktop and it will apply. Then go into game mode and play!
Overall pretty nice. I haven’t used NonSteamLaunchers much since I don’t normally need other launchers besides heroic, but the dev continuously adds a lot of nice stuff it seems.