If you see a cfg or ini matching your resolution, delete it and it may reset your chat position
Comment below rating threshold, click here to show it.
It gets lost when you swap the minimap. I swapped mine and the chat box disappeared. Try swapping your minimap position (in more options, I believe) and the chat box may reappear. Then more the chat box to the middle of the screen, re-swap the minimap position, and you should be able to keep the chat box in view and move it to where it was