Have a glass of water at the ready. It always helps to soothe my nerves and if I get stuck on answering a question, taking a sip gives me time to think things through. It’s also practical because if you’re doing most of the talking you’ll end up with a dry mouth and no one wants to croak during an interview.
All this applies for both video call interviews or on site, in which case ask for a glass of water before you start the interview.