An independent chairperson for the viva can be really valuable. They act as an impartial observer, recording what happens. They can be a navigator carefully steering examiner or candidate away from fruitless discussions. They don’t decide the outcome but they can help set the tone for a good viva.
And not every viva has one. If you don’t, then your internal examiner takes on some of these responsibilities. They’ll make sure your viva is fair.
Is there a chair or not for your viva? Find out. One situation isn’t better than the other – they’re just different. Knowing as much as you can about what to expect can help settle your mind that your viva really is going to be fine.