She may fall under Beverley's staff, once she started wearing a uniform it was the medical colors.
She wasn't wearing medical colors, she wore science blue. Crusher was in charge of the medical staff (except for the nurses, wouldn't make much sense to have a doctor be their boss)
, not everyone in a blue uniform.
Am I reading this wrong? Why wouldn't a Chief Medical Officer have authority over nurses, who are medical personnel? I'm pretty sure nurses are usually required to follow doctor's orders.