NUI

Set to 3 different clues across 8 published puzzles, most often “Rapa ___ (Easter Island)” — The New York Times, Friday, 24 June 2011.

3 letters

Every clue on record, most used first

Rapa ___ (Easter Island)6 times
The New York Times — Friday, 24 June 2011
Air Tahiti ___ (carrier to Papeete)once
The New York Times — Friday, 15 December 2006
"Mahalo ___ loa" ("Thank you very much," in Maui)once
The New York Times — Sunday, 5 March 2000