Open 8x8 Work Desktop application and go to "Meeting" tab, then to "Recent meetings" tab. Click it.
Search a meeting that ended and has "Meeting chat" option in "Meeting resources", exactly under "Participants". Click it.
On top of the 8x8 Work Desktop window, you will have a pop-up window named "Meeting chat" , that will show everything that was written in that meeting's chat.
You can scroll down and up, to see all the messages.
You now have access to everything that was written in the meeting's chat, that you did/didn't participate in.