The way I determine if a hen is a committed broody that deserves eggs is that she spends two consecutive nights on the nest. One night is not enough. What she does during the day is not enough. Many hens look and act broody but are not really committed.
I don't know what your coop looks like, how many nests you have, how much room you have, or how many chickens you have. That kind of stuff would influence my decision on what to do. I see that you have two basic options.
The way I do it is to mark the eggs I want the hen to hatch so I can tell at a glance which eggs belong (I use a black Sharpie). After the others have laid for the day I check under the broody and remove any eggs that don't belong. As long as you remove them daily you can use them to eat.
The other option is to lock her in a nest until the eggs hatch. You need an area for the nest, food, water, and a bit of room to poop. Many people build a separate "pen" for this, in the coop or elsewhere. Some people build a pen around her current nest. This depends on what your nest and coop look like. The idea is that she is separated from all the other hens until the eggs hatch. She can't get out and they can't get in.
I don't know which is the best option for you. There are risks no matter which way you go.
