Correct, Nicaea II had nothing to do with it.
It was three councils around the year AD 400, in Hippo, Rome, and Carthage. I fail to see how that gets you off the hook.
Furthermore, the task of the council was not to imprimatur the New Testament, but to distinguish it from forgeries--a purely forensic task.
This is simply ahistorical nonsense. There were a number of quite worthwhile and nice books read as Scripture in the early Church -- the Epistle of Barnabas, the Epistle of Pope St. Clement, the Shepherd of Hermas, etc.
They weren't "forgeries" at all, and it wasn't a merely "forensic" decision to determine that they were to be left out of the canon. And it wasn't a merely "forensic" decision to decide to include other books that were controversial, like Revelation.
The implication that the Church therefore supercedes scripture is absurd, although perfectly orthodox Catholic teaching.
Maybe you should let Catholics teach "perfectly orthodox Catholic teaching," and not try to tell us what we believe, hmm? The Church certainly doesn't "supercede" Scripture, she obeys it. But she also, historically, recognized what was Scripture and what wasn't.
Meanwhile, no decision of any pope or council is of any interest to me, least of all the decision to condemn sola scriptura as a heresy.
Sola scriptura, not being found in the Bible, condemns itself as heresy.