My understanding is that it is a temporary GRAB of DV lottery visas and passed to the other program. The Nacara program is big - some years in the early 2000's having 30k visas so I think they cobbled together the NACARA allotment from various places, DV lottery included.
Now then, this conversation made me go look a little more - and I admit I am a bit excited. The NACARA program appears to have had two main parts - 202 and 203. Wikipedia shows from 1999 to 2005 around 180,000 people got visas through the program, so it was not a small deal. However, the timeline for entry into the program (people who sought asylum in the early 90's) must mean that the demand is tapering off these days and Wikipedia figures show a glipse of that. There have probably been changes to the program and I don't have numbers at all to support this, but I imagine that the number of NACARA cases taking visas from DV2014 and beyond must be quite small. The wording in the DV instructions says the NACARA program will be assigned "up to" 5000 visas, so if they take less, then we get those back in to the general pot (not just for SA).
SO THEN - that means another possible explanation for the 35,000 extra visas this year is that they are actually trying to fill ~55,000 visas as opposed to 50K. That really would have a dramatic effect for winners - we could see much higher case numbers getting happy than we thought. I hope that is correct....