Dr Nielsen completed orthopaedic surgical training in metropolitan and regional Queensland hospitals. He has been awarded a subsequent subspecialty-certified fellowship in spine surgery, with a particular focus on anterior reconstruction of the cervical and lumbar spine, as well as posterior spine reconstructive surgery.
Dr Nielsen holds a public position as a specialist orthopaedic surgeon at Brisbane's Princess Alexandra Hospital, where he is part of the spinal trauma team, and also treats a wide range of elective spinal conditions.