It's actually the right hand thread that is NLA. They changed when they started making the close ratio transmissions in the 280ZX. The LH Thead M27 x 1.0mm is used in a variety of models like the Urvan, Infiniti, 240ZX, 280ZX, 300ZX, 720 trucks etc.
The RH Thread M27 x 1.0mm has been NLA for a very long time. Someone on this forum made some for other members a while back.
You can re-use the original nut if you can open the indented section and remove it without to much trouble. When you rebuild and it lines up on the used section of the nut, you have a couple of options: 1. Machine 0,5mm of the nut face, then the nut will turn a furthe 180° or 2. Use 0,5mm shim. Any thickness will do as long as it is not 1, 2 or 3mm.