Xbox One rolled out an amazing update for the Twitch app. You can now include party chat in Twitch Broadcasts! If you are broadcasting from your console and in a party, you can invite other people to include their chat audio in your broadcast by enabling “Broadcast party chat” in the Twitch app settings. If a member declines, they will still be able to chat in the party, they just won’t be heard in the broadcast. As the party leader you have the option to mute a party members chat audio, even if they are opted-in.
You can now Include Party Chat in Twitch Broadcasts on Xbox One
What settings do the people in my party need to have on to include their voice in the stream?