I thought I would give a little update on how the chicks and hen are doing!
The first night didn’t go that well, and I woke up to find a dead squished chick under the hen

… the chick was smaller than all the other chicks at the feed store (we didn’t get to pick the chick, the workers at the feed store just grabbed a random one). But the other chick was still very strong and healthy and wasn’t squished.
We decided to go to a different feed store with different breed options and got two more 3 day old chicks the next day. Before giving the chicks to the mama hen we rubbed a little towel on the hen to get her scent on it, then gently rubbed that on the chicks so they smelled like they hatched under her. She accepted them right away!!
A couple hours after we gave her the other chicks she left the nest and took the chicks to the food and water and they all hung out there for a while. The hen has been very protective of the chicks from the rest of the flock, so we decided to put up a small wall in the coop to make a brooder for the hen and chicks until they get a little older.
The chicks did great all night and our hen is doing so much better at caring for them and seems to be a lot more gentle when they go under her and the chicks enjoy popping their little heads out from her wings
Thank you so much for everyone’s helpful information!!