Yes, the Nikon Z6 III is compatible with the ProGrade Digital CFexpress Type B Gold 128GB.
ProGrade CFexpress Type B Gold's 128GB SKU has a rated write speed of 260 MB/s (manufacturer's own page, capacity-specific). Nikon Z6 III's own online manual requires cards rated at least 250 MB/s maximum data transfer rate for high frame size/rate video (4K60) -- this card's 260 MB/s write rating exceeds that number.
Limitation
Card's rated write speed (260 MB/s) clears Nikon Z6 III's stated 250 MB/s requirement for this camera's most demanding video mode by a modest margin -- no independent third-party benchmark confirms real-world sustained performance at that rating.
“CFexpress or XQD cards with a maximum data transfer rate of at least 250 MB/s, or UHS Speed Class 3 or better SD cards with a maximum data transfer rate of at least 250 MB/s, are recommended for recording and playback of videos with a high frame size or rate.”
“Read 1700MB/s | Write 260MB/s Sustained write 250MB/s”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)