Whoa!  The Council of Nicaea did establish a Christian creed (statement of beliefs, or profession of faith) that affirmed the divinity of Christ, as seen in the statement: “We believe in one Lord Jesus Christ, the only-begotten Son of God, begotten from the Father before all ages, God from God, light from light, true God from true God, begotten not made, of one substance with the Father . . . . “  As I document elsewhere on this site (see here), a great many texts (including the books of the New Testament) prove that many Christians thought of Jesus as divine long before the Council of Nicaea.  The Council of Nicaea did not discuss the matter of Jesus’ divinity as such (most Christian groups accepted Jesus’ divinity in one form or another), but it did discuss the question of whether Jesus was fully divine, and it did affirm his full divinity against those (namely Arius and his followers) who claimed that the Son’s divinity was not equal to that of the Father.