You need to do some research, my friend. Both your facts and interpretation of them are incorrect. The Nag Hammadi collection has next to nothing to do with the NT; they are mostly gnostic writtings.
About the NT being shaped in the council of Nicea? I'm sorry but, what kind of "Da Vinci code" nonsense is that? Nicea had nothing to do with the canon. The purpose of the council was to discuss the person of Jesus (i.e. whether he was of the same substance as God or just similar but inferior to God the father.)