Just thought I'd post this video tutorial I made because I figured this stuff out myself and thought it might be useful if people need to do this themselves. You just need Livestreamer and VLC installed and the "video source" plugin for OBS. There are links in the actual YouTube description if you need help finding it.

You can always get the twitch HLS URL with this http://bog.no-ip.biz/sc2/stream2vlc.php#justin|adam_ak Should be easier than running livestreamer.

That's one of the first things I tried but when I tried it last, if I put that URL into the video plugin it just wouldn't ever show anything. Does it work for you?

EDIT: Tried it again with the plugin up to date just to check and it still doesn't work. I guess the version of VLC it uses doesn't work with HLS streams?

I didn't try anything. Maybe OBS or that plugin can't work with HLS. Livestreamer converts everything to RTMP.

From when I got Livestreamer to print the actual URL it was using (for Twitch anyway) it was pretty much the same thing that the Stream2VLC site gives you. It's just the fact that Livestreamer can output another HTTP stream that works with the video plugin that makes this work.