Any music service can add itself through Sonos’ free, open API.  If you want Twitch on Sonos, you need to lobby Twitch.

Not sure how easy that will be, but I'll have a go! Thanks

If it helps, you could point them to the Sonos partners page.

When I found out people were DJing on twitch, my first thought was that I wanted to be able to play the audio around the house. I love my dark and progressive sets. I didn’t know how to make it work in the beginning either. I have some answers for you below. *jazz hands*
 

Twitch is a video streaming service and not a music streaming service. It’s unlikely or not possible for the service to be added for direct play in the Sonos app in twitch’s current form.

I had all Play:1s when I decided I have to get twitch sets to my Sonos system. There are a couple ways to do this.  Airplay 2 is one way, but the Play:1 doesn’t have that capability. The newer Sonos speakers, like the One, do have that capability. In fact, if you have just one airplay 2 capable Sonos speaker, it can steam that audio to the Play:1s.
 

The second way is to add one of the Sonos soundbars (Ray, Beam, or Arc) and then use the twitch app on an Apple TV or other streaming box to stream the audio. The Play:1s could be used as surround speakers with this setup.
 

The cheapest way would be to see if your Play:1s have the 15% upgrade discount, upgrade them to a pair of Ones or any newer sonos speaker, and sell your Play:1s. I sold mine for around the same price I originally paid for them.

I chose to add a Beam soundbar and played the twitch app from my Apple TV. It’s awesome because you can watch the stream on tv while the music is playing everywhere. I wish I had known DJs were on twitch at the beginning of the pandemic. I was upset when I realized I needed to upgrade before it would work, but I’m dedicated to my music, and it was totally worth it. I hope my lengthy little breakdown helps.