This is why you should read The Heresy of Orthodoxy (my review). What Glen Beck basically says here is the type of Conspiracy theory of Christianity that we find popularized in the Da Vinci Code. Unfortunately, for far too many this is the kind of thing that if it just gets repeated enough, it suddenly becomes "true" or at least it seems to be a "credible theory." Historical disciplines should quickly dispel this.
There are so many errors in this two minute clip it isn't funny. The council of Nicea had really nothing to do with the making of Scripture and the binding of it. For all Constantine's flaws, he didn't invent the Bible or orthodoxy.
The Dead Sea Scrolls are Jewish documents, some of them OT scrolls. The Dead Sea Scrolls were buried long before the Council of Nicea. The DSS were probably buried by a Jewish sect known as the Essences, although that could be slightly debated. But they aren't even remotely Christian.
Although what Glenn Beck says about the DSS is what most people, even scholars, basically think about the Gnostic Gospels. This is popularized by the Bart Ehrmans and Elaine Pagels.
The things confessed in the Nicene Creed trace their history back through the Rule of Faith, the early church fathers, and into the New Testament itself. It is true that the nature of the some of the argumentation develops along with the vocabulary, but simply reading Athanasius and the church fathers defending Nicea, you quickly realize the issue is about expounding the true teaching of Scripture--and holding to the things which the church had confessed from the beginning.
To dispel some of this, I'd also recommend Darrell Bocks The Missing Gospels, although with the works of Darrell Bock, Ben Witherington and Craig Evans, and others, on the historical Jesus.