If the chick is under a broody, step aside and let mom do her job. Chicks don't need to eat for at time of hatch. Though it is our instinct to get in there and meddle with mother nature, it is usually wise to leave the natural process to nature. Leave mom alone and let her do her job. I usually check in every couple of hours to make sure things are going well.
Give the chick a day or so to acclimate to being out of the egg. He or she has enough energy to live a day or so without feed. This is how nature designed the hatching process for chickens. Other farm animals need to suckle within a certain time to get maternal antibodies. Chickens, on the other hand, are hatched with what they need to survive for a day or so.
If you do decide to step in be sure you have a setup to keep the chick alive. You must have a warm, dry place that will keep it safe from other critters. You'll need a heat lamp and so forth. Medicated chick crumbles are the best to start with and supply water with an chick approved device.
Good luck! Hope this helps.