As of May, 2023 from Promptchat Version 3.0.4 Instagram is available for the ChatBoard (Team Inbox), Chatbot builder Instant Messenger and Campaigns.
See the setup guide for adding Instagram integration channel:
https://docs.google.com/presentation/d/1NIfS70ILG-j9ALQPESdGqCcVXCyLUfOkN0nTUv6lIjk/edit#slide=id.g239971f29d3_0_89