This adds a Twitch Chat overlay right into the game, as well as a couple chat commands that can be used.
To install, extract the zip into
C:\Users\Username\Openplanet4\Scripts\ and set up your OAuth token, username, and channel.
Make sure you check the settings for the plugin as there are quite some things you can tweak:
This uses Twitch Chat Integration, which is included with this file as well.