How do I get Fortnite In-Game Party Chat audio to broadcast to twitch?

Hello dear Gamer, first it's a pleasure to be able to help you today.

My name is Vinicius.

I am a gamer and independent advisor on the XBOX community platform.

Hey CharlesGamer, how are you today? Hope you're well.

You would have to configure the stream to enable the chat of Xbox and also, all of your friends, that are in the party, have to set their privacy settings to allow their voices to be shared in a stream.

Method 1 – Xbox Party Chat

Xbox has a feature built in allowing you to share your Xbox Party chat through the Twitch app. However for this to work everyone in your party chat will have to confirm that they allow their chat to be broadcast. This will allow your Twitch chat to hear anyone that you are playing with in your party. Your Twitch chat may still not be able to hear other players that are in your game depending on the game you are playing.

Step 1 – Start A Party

The first thing you need to do is start a party with your friends. To do this hit the Xbox Button on your controller to open the menu and then select Parties and Chats –> Start A Party. You can then select Invite more and invite your friends to your party.

Step 2 – Allow Audio To Be Broadcast

If you want to broadcast other people’s audio you will need to make sure that they select the “include my audio” checkbox in the Xbox Party Chat screen. To do this click the Xbox Button and then Select Parties and Chats –> Include My Audio.

Step 3 – Set Party Chat Volume In Twitch Chat

You now need to make sure that your party is not muted in the Twitch app on your Xbox. To do this go to the Twitch app, move down to the audio sources and un-mute Party Chat. Here you can also adjust the volume of the party chat to balance your friends audio levels compared to your mic volume on the stream.

Method 2 – In-Game Chat

In certain games you are able to hear your in-game chat on your stream. This means that in some games you can play with Randoms and your Twitch stream will be able to hear the people you are playing with. However there is a lot of games that do not allow you to broadcast game chat due to privacy reasons. You will need to check if the game you are playing allows broadcasting or not.

Your friends have to open the party on their consoles and check the box that says "broadcast my audio" I believe, or their voices will not be included.

are your friends going into the party chat and saying 'broadcast my audio' ?

Hello,

Xbox Clips feature are just record video/audio from current game, without your party voice chat. If you need to record video with party chat you can try to start broadcasting with Twitch (dont forget to record party chat in your broadcast settings), and
then create clips from your past broadcast.

I'm Samy an independent advisor. Welcome to the Xbox community. How are you?

Unfortunately, this is not possible. If you make a broadcast on Twitch you can save the broadcast and the party chat audio will be included. If I'm not mistaken, to include the audio in the clip it is necessary to use an external capture card.