I'm not hugely experienced but I did have problems with my previous broody never coming off the nest for her food and water; she nearly died and was never the same again after rearing her chicks. So with my current one she always has water in the coop but once a day she gets a bowl of mixed grain and a bit of grit put outside the coop and I actively watch her to make sure she comes out, stretches, eats loads, nibbles some grass, drinks, and poos before she goes back on her nest. I do this at the same time every day.
She (a pekin) is in a nest of shavings in a 12' cube cardboard box with a door cut in it. This is placed inside a small coop (3'x2') with a mesh window for light and air - not much different to a rabbit hutch. Outside she has a 4'x3' run so the other hens don't bother her. The nest is not facing the window. My previous hen reared her chicks in the same arrangement. Hope this helps.