Leaving aside the non-trivial question of candidate nervousness in live coding, I do find the "ask questions about take-home" process very illuminating.
If it came from a friend or chatGPT, you'll learn that quickly because you can ask them stuff like "show me how you're implementing FOO. OK, if the requirements change, and now we need to BAR, what do you need to change across the app?" If they wrote the code and understood the task, they should understand what needs to change, how to do it, etc, and you can do that part with them live. Maybe someday LLMs will be fast enough that you can't catch someone constantly waiting for the AI to help them, at least as of May 2025 we're not there yet.