The Nicene Creed is a long-standing tradition in Christianity, and "defines the mainstream definition of Christianity for most Christians". It has been independently accepted by the Catholic, Eastern Orthodox, Lutheran (pdf link), and plenty of Protestant churches.
Joshua Christian seems to have presented a fanciful (or at least misleading) view of the formation of the Nicene Creed. I could find no other sources that back up his story. Here is the account of the Creed's creation, as I understand it.
Sometime before 325 AD, around 1800 Christian bishops (every bishop Constantine knew existed) were invited to convene in Nicea. We have no way of knowing with 100% certainty how many bishops actually showed up, but the traditional number is 318. Athanasius of Alexandria counted 318; Eustathius of Antioch estimated 270.
Please note, this is only a count of bishops. Each bishop was allowed (and encouraged) to bring deacons, priests, or other traveling companions. Only the bishops had voting rights. Therefore, it is entirely possible that there were 2030 total people in attendance, with only 318 votes cast. Only 318 votes could be cast, because only that number of people had voting authority.
Addressing Constantine's supposed power over the council: I will concede the point that Constantine wanted a Creed to be developed in order to "forge a 'unified' church". That seems likely, by the fact that he arranged for the council to meet. However, I disagree that Constantine cared that this particular Creed pass. At this time, Constantine was not even Christian (he was baptized 12 years later, in 337 AD)! It would make sense for him to go along with whatever Creed naturally came about during this council.
As further proof that Constantine's meddling was not the theological backing of the Nicene Creed, there was a Second Ecumenical Council that met in 381 AD (40+ years after Constantine died) and confirmed the Nicene Creed. It should be noted that the Second Ecumenical Council did not have overlapping members with the First Ecumenical Council, as it was held 56 years later.
Addressing the Arians. Arianism was, indeed, a major topic for the Council of Nicea. The debate centered on whether Jesus co-existed eternally with God the Father and the Holy Spirit (a trinitarian view) or whether Jesus was created by God the Father at some point prior to the creation of the universe (a non-trinitarian view). Arius, a priest in the Alexandrian diocese, claimed that Jesus was "born" and was, therefore, different in essence from God the Father.
Initially, 22 of the 318 bishops came out in support of Arianism. However, after the writings of Arius were read in the council, and after hearing arguments from many of the other bishops, the 22 Arians came to believe in a trinitarian view of the Godhead. Arguments that swayed toward the trinitarian view included John 10:30, where Jesus says
"I and the Father are one" and John 1:1, which says
"In the beginning was the Word, and the Word was with God, and the Word was God." Each side of the debate had ample time to make a case: the debate lasted for over two months!
In the end, the majority of the 318 bishops agreed upon the trinitarian view presented in the Nicene Creed. Arius was exiled, along with Theonas and Secundus, to Illyricum. None of those three were bishops, so they did not have voting authority in the council.
Three bishops, Theognis of Nicaea, Eusebius of Nicomedia, and Maris of Chalcedon, remained believing the Arian view of the Godhead. They chose to sign the Nicene Creed anyway, out of deference to Constantine.
In the end, all 318 bishops in attendance signed the Nicene Creed. Out of those, only 3 bishops chose to sign without fully believing the Creed themselves. There were only three people exiled (and those, only to another province in Rome).
Joshua Christian misses the forest for the trees. He is correct that there was political and religious pressure. He far overstates that effect on the Creed as a whole.