I used ChatGPT to ideate and create the first iteration of several board games, of which two survived to the prototype phase.
The prototype games are:
"Spacewalkers" - the space exploration game.
https://docs.google.com/document/d/1ytPtHr8Ei7ciNyXHGKjVVzL4IsdEBK-cPsosDpeJoyg/edit?usp=sharing
"Epic Math" - the game about the history of mathematics.
https://docs.google.com/document/d/1nfwlp1TkKKyxSoU51-KBMkG1uh-ypi6TlMWy7ZZPlUk/edit?usp=sharing
ChatGPT also helped me deate a game about the history of the Universe, from the Big Bang to the far future, and several smaller games which did not pass the ideation phase (but may pass in the future).
Of the two prototype board games, "Spacewalkers" gathered attention of Sierra Madre Games and at least its mechanics inspired another design (the game "Arrival"). It is possible that SMG may consider publication of the "Spacewalkers" - the negotiations will take place.
In order to create a board game you need to know the restrictions of the context. Sooner or later it will be lost, so do not be too verbose and let it also not be. The best way you can use LLM in the board game design is first to talk about your concept, ask about some minimal rules (even childish and cheesy) to iterate with. Also ask for a tabular list of possible cards or other components, and modify the list by you, human. After having such lists and rules, you can let ChatGPT rewrite the rules and lists based on its recent additions tot he list and rules. To some extent you'll receive a stable and working concept, albeit incomplete and unbalanced. It is now you, the human developer, to continue development. When you condinute, paste your current rules and shrinked component list for LLM to comment upon. Another good thing is that LLM can be asked to imagine a typical turn or a situation in the game. It will give you important UX design cases.