In the context of contributing to our theoretical infamy among the Garlean populace? No, Nael doesn't count. Only a select few Eorzeans (namely the Scions) know about the events that occurred in the Coils; I highly doubt the average Garlean citizen is aware of that.
I deliberately said "chumped," not "killed." If you want to be technical about it, non-Legacy Warriors of Light haven't actually killed any legates. They have defeated 3 but none actually died by their hand. Gaius was defeated and had no way to escape the exploding Praetorium, Regula was defeated twice (once in undeniably canon single combat) and sacrificed himself to save Unukalhai, and Zenos was defeated but committed suicide. Nael was the only clean kill. Another detail the Garlean citizenry probably isn't aware of, but I digress.
(I'm aware of the whole Nael / Eula thing, but it's a phantom distinction. Regardless of name, she was still Legatus of the VIIth Legion, and Nael is just the more commonly used of the two.)