Wow memory lane, I broke mine YEARs ago when colored Nissan Plastic was easy to aquire for a price. I had to take a new key as they couldn't match that, but I just wanted to latch the darn thing.
There is a great website and I am sure you can get a replacement for it
http://www.300zxpartsforyou.com/
this dude has everything in color matching. I never EVER locked that darn thing again and learned the hard way to be VERY gentle wiht expensive (and now very hard to find) nissan plastic.