The Nicene council was called in reaction to the Arian heresy, which “denies that the Son is of one
essence,
nature, or
substance with
God; He is not consubstantial (
homoousios) with the Father, and therefore not like Him, or equal in dignity, or co-eternal, or within the real sphere of
Deity.” (from
newadvent.org/cathen/01707c.htm)
The Council had to discuss Jesus’ divinity because they needed to define it, so that it could be clearly seen that Arianism was heresy.
You could jokingly say that Arian was responsible for that part of the Creed that says, “We believe in one Lord, Jesus Christ, the only Son of God, eternally begotten of the Father, God from God, Light from Light, true God from true God, begotten, not made, one in Being with the Father.”
