Nicholas was the founding coordinator of the Institute for Professional Practice in Heritage and the Arts at Australian National University. He has worked on heritage management at key heritage sites in Australia, including Uluru–Kata Tjuta and Kakadu National Parks, and sits on the Uluru–Kata Tjuta National Park Cultural Heritage and Scientific Committee advising the park on cultural heritage management issues.

Internationally, Hall has helped establish World Heritage management programs in Vanuatu, conducted training for UNESCO in Indonesia, worked for the World Monuments Fund on Easter Island, and has provided advice on heritage and tourism management for the Angkor World Heritage Site in Cambodia, including participating in the preparation of the Tourism Management Plan for the Angkor World Heritage Area. He has an ongoing involvement with the GCI to improve rock art conservation practice internationally. As part of this work, he was a coordinating author in 2015 of the Getty publication Rock Art: A Cultural Treasure at Risk: How We Can Protect the Valuable and Vulnerable Heritage of Rock Art..

His professional interests center on rock art management, cultural landscape management, planning in cross-cultural contexts for land and heritage management, and appropriate use of heritage in tourism development.