The Nicene Creed contains the essentials of the Christian faith. Without holding to that, one is not even a Christian (let alone a Catholic)
To say the Nicene Creed is the only thing needed to be a Christian and thus denying other things does not render you as a non-Christian is heretical. You don't know fundamental concepts about membership in the Church. Those who deny Catholic teachings are not in the Church.
Eugene IV,
Council of Florence, Bull “Cantate Domino,” 1441, ex cathedra:
“It [the Holy Roman Church] condemns, rejects and anathematizes all who think opposed and contrary things [to the Church], and declares them to be aliens from the Body of Christ, which is the Church.”