Aravindhan, I too could not find any thing on Nacchinakkiniyar by google. It will be nice if you can tell us about his theory sometime.
This makes it likely that the dedicated long matra, too, was first introduced in a Tamil context, and that the resulting system was only later imitated in Bhattiprolu. No such Tamil inscription has however been discovered yet." I refer to the last sentence. Does the discovery you mentioned provide this missing link?