NRT is not heavily split in the current catalog, but the short label still hides the underlying IANA zone and any future policy change. The safe pattern is to write the abbreviation for humans and the zone for machines.
NRT is a small-country civil label at UTC+12; it should be written with Pacific/Nauru when precision matters, especially because NRT is also an airport code. Not the same as FJT or NZST: Nauru has a distinct jurisdiction and operating context even when the wall clock matches.
Pacific/Nauru sits at one of the far edges of the offset spectrum (+12:00). Pages and software that assume "close to UTC" often render NRT incorrectly, so explicit handling is more important here than on UTC-adjacent zones.
For precise work, the safest equivalent of NRT is the exact IANA zone used by your city or system. Pacific/Nauru sits at +12:00, ahead of UTC, which means daily logs in this zone reach a new calendar date before UTC does — a small detail that breaks date-based reporting if missed.
Within this single zone (Pacific/Nauru, +12:00), NRT is unambiguous, so the abbreviation and the IANA zone effectively interchange.