They'll be fine! At night they'll be roosting and won't even think about eating - they won't eat in the dark anyway.
Are they making really fast chirping sounds? If so, that's completely normal for chicks just learning to go into a coop at night. Give them a few weeks and they'll know what to do when it starts getting dark!
Are they making really fast chirping sounds? If so, that's completely normal for chicks just learning to go into a coop at night. Give them a few weeks and they'll know what to do when it starts getting dark!