Brightcove Interactivity Custom Form widget can also be used to display content from another web page. In which, you can add the chat or Q&A inside the widget. Please take note that the chat or Q&A need to design properly, such as with the transparency element so that it will not block the video itself. 

Please refer to this URL for more details: https://studio.support.brightcove.com/interactivity/widgets/embedding-form-video.html