Sorry. The Council of Nicea didn’t decide what the Bible is. It was a Bishop who went to the conference. Right after the conference he received a letter asking him which books which were good to use and which weren’t. He made a list and sent it out. The letter got popular and they called a new conference right away, then voted on his list. The Council of Nicea dealt with an issue of the Trinity, declared that there was one church of the Christian people and it was Catholic, and a procedural issue about rules governing Bishops.