I originally downloaded the snapshot while my save file was located in the Nether, and when I started the game when I had the snapshot, I walked around for almost 30 minutes, but I never found any Nether Quartz Ore. I was also walking around chunks that had been previously loaded, so I don't know if that had anything to do with it.
I also created a new world with the same seed in creative, and the Ore spawned just fine.
New features don't spawn in previously generated chunks. New chunks need to be loaded in order for the features to appear.