Not sure why this is on HN. Council of Nicaea is a favorite flashpoint for conspiracy theory people. But in reality it wasn't all that special. It was just one event in many that shaped Christianity. Basically its like a ISO Standards meeting. Lots of old guys making obscure arguments based on interpretations of obscure text about things that essentially don't matter outside of a bunch of nerds.
The connection between their arguments and the actual resulting Christian practice is tenuous at best or more likely irrelevant.
And all things considered its pretty late in the formation of Christianity of the Church. By 325 the church was pretty unified on the most important things.
Its just more famous because we have slightly better documentation for this history. We have almost nothing for the first century. In the second century our records are incredibly spotty and fragmented. It gets a bit better in the 3rd and 4rd century.
There is so much interesting 'Christian' history of the early 2 centuries that people are totally unaware off. If you want to see into some of that strange history, you might want to read something like: "Found Christianities: Remaking the World of the Second Century CE"