My hens regularly hatch in nests 2' or 4' above the coop floor. The hen has no trouble getting the chicks out when she brings them off of the nest. She says jump and they do, then bounce up and run to her. I saw a broody get her chicks out of a 10' high hayloft that way. They jumped, bounced, and ran to her.
I had a chick fall out of a nest one time. I let a hen hatch in a bucket nest with the top of the bucket 7-1/2" x 11". When the chicks climbed on top of Mama and fell off, they missed the nest and hit the ground 4 feet below. She was covering the side so they could not hit the nest in the way down. Four different times I picked a chick up off of the coop floor and put it back in the nest. It was probably the same chick each time. I retired that nest after that hatch.
It looks like your nest is big enough that the chick will not fall out if it climbs on top of Mama and falls off. I personally would not worry about that.
I don't know how much room you have in your coop or outside. I let my hens raise their chicks with the flock from Day 1 and have never lost one to another adult chicken. One time a two-week-old chick killed its hatchmate sibling while the broody hen did nothing. I had another 2-week-old get into a pen of 8-week-olds where the broody could not protect it. They killed that chick. I had a broody kill two of her own chicks and raise the other 6 fine, I have no idea why.
I have never had a dominant rooster threaten a chick. Other people I trust on this forum say they have had roosters kill chicks. Sometimes a cockerel or another hen will threaten a chick. Mama whips butt. None want to face an angry Mama hen. Some people on this forum I trust say their broody hens did not protect their chicks. Mine always have. With living animals you never know what will happen.
I think the more room you have inside and outside the easier it is for Mama to take care of her chicks. I don't know how much room you have but if room is that tight you may have trouble integrating them later if you separate at first. As you can see from the other posts many people do separate the broody and chicks, at least for a while.
If you do separate them I strongly suggest you make sure a chick cannot escape and leave Mama's protection. There have been posts on here where a chick was killed by the flock when that happened. No matter what you do there will always be some kind of risk.
Good luck!