No in the case of an expert witness. And ChatGPT is not, should not and can not be party to any legal proceeding. It isn't even remotely ethically sound to help people twist facts for their own purposes.
I agree that there are ethical problems around helping people twist facts for their own purposes. My point is that everyone in a courtroom except the judge and jury are there to do exactly that. They make the strongest possible case to get their desired outcome from the available facts.
You see a solemn man looking at a cup and see a man lost in thought; I see a man irritated that the waitress hasn't returned yet.
Courts are all a show. It doesn't prove which side is "right," only who can make a more convincing argument. LLMs are a natural fit. There is no such thing as justice.