Don't worry. She won't break if you need to pick her up or give or take eggs. Her hormones have her pretty much programmed to keep sitting on a nest no matter what. Of course, there is an occasional broody that will get "out of the mood" if she's moved or if there are other stresses, but those hens aren't usually seriously broody anyway.
Usually, a broody will get herself off the nest at least once a day, usually during the warmest part of the day so the eggs don't cool rapidly, and she will spend less than five minutes depositing a huge smelly poop, getting a small bite to eat, drink a considerable amount of water, and likely do a quickie dirt bath since she's a prime target for parasites sitting still on a nest all day and all night.
If you do not see your broody get off the nest, and it's a real trick to actually catch her in the act since she's back on the nest again so quickly, I strongly advise you take her off the nest and scoot her out of the coop to take care of business. I have a star broody who would likely sit for a straight week before dragging herself off the nest. It's advisable to make sure she gets off the nest once a day.
For the most part, the broody has it covered, and you don't need to do much, if anything. After three weeks of incubation, the eggs hatch, and the broody hormones then switch from sitting on eggs to caring for the chicks, and she will be getting the chicks out and about within the first two or three days. Provide water and chick crumbles or all flock feed for both mama and chicks within easy reach on the floor.
Beyond that, consider her and the chicks' welfare when the eggs hatch. Are they in a nest on the ground so the chicks can get out of the nest easily and back in? They do not hop or fly for the first two weeks. Is the nest secure against other hens laying their eggs on top the incubating eggs? I've had this happen and have lost incubating eggs to breakage. How about the safety of vulnerable chicks if there are mean hens? How predator proof is the nest? These are things you may want to give some thought to before the eggs hatch.