Broody hens have been managing hatching eggs since before they were domesticated. Relax and let her manage the process.
No two broody hens are identical, but most come off the nest daily to eat, drink, and go poo each day. Usually a big stinky poop since she has been holding it for 24 hours. I’ve seen broody hens come off and stay an hour at a time, twice a day. I’ve seen broody hens come off once a day for only 15 minutes. I’ve had broody hens I never saw off the nest, but since she was not pooping in the nest, she was coming off, just not when I was watching her.
If you have to, you can take her off the nest once a day and toss her in the run outside. She may eat and drink or she may just go back to the nest. It won’t hurt anything. But it isn’t necessary.
