A
Chief Commissioner is a
commissioner of a high rank, usually in chief of several Commissioners or similarly styled officers.
Colonial
In
British India the gubernatorial style was Chief Commissioner in various (not all) provinces (often after being an entity under a lower ranking official), the style being applied especially where an elected assembly did not exist, notably:
Independent Commonwealth nations
Australia
On two occasions in the late 20th century, local elected government in the City of
Melbourne was temporarily replaced by panels of commissioners headed by a Chief Commissioner.

Commissioner is also a rank used by Scouts Australia for Adult Leaders in a Region- or Branch-level support role. District Commissioners are the highest authority within their District and can enter any Scouting property in their District at any time.
Mauritius - Rodrigues
The
Chief Commissioner of Rodrigues is the gubernatorial head of the
Rodrigues island regional government since it was granted autonomy within the independent republic of
Mauritius. The Commissioner comes from the party holding the most seats in the regional assembly.
The incumbents were:
However the Chief Executive of Rodrigues is in daily charge of the island administration.
Sources and references