Probably too far-fetched, but curious anyway since this would make things a lot easier.
Recently got a modded Switch with a chip and it's got custom software with this Tinfoil app on it, and I was wondering if it could be possible to somehow stream to Twitch/YouTube directly, without a capture card, using an app that would work only with a modded version of the console.
Hmm... bluntly, a lot of games struggle to hit their target framerate on the Switch as is. I'm not sure there's available overhead to implement streaming. At the very least, I've not heard of anything either!
If you don't want to buy a capture card, but have a PC, the easiest way may be to dump your games and run them on an emulator like Yuzu, so you can stream from the PC.
I have a cheap ebay 10 usd hdmi capture thing that plugs to usb and gives prefectly fine 1080p 30fps stream as a fake webcam and I use my computer to do the rest