"When this is done, the Nicene Creed shall be sung or said."
The first act of newly-ordained priests in the 1662 Ordinal is to join with the bishop and the church in proclaiming the Symbolum Nicaenum. It is a powerful statement of the calling given to the presbyter to ensure their ministry of teaching, proclamation and catechesis conforms to and flows from the Church's Trinitarian and Christological confession.
In a singular way, of course, the calling to safeguard the deposit of faith is given to the episcopate. (No better contemporary exposition of this can be found than Blessed John Paul II's Apostolic Constitution Fidei Depositum.) That said, presbyters have a share in this ministry with their bishop. It is presbyters, after all, who preach, teach, catechise, absolve, counsel and pastor in a local context. And the shape of preaching, teaching, catechesis, absolution and counsel, and pastoring is fundamentally determined by the Church's Trinitarian and Christological confession. ...
The content of the presbyter's ministry of proclamation in Word and Sacrament - "the tradition that comes from the apostles" - is given to and received by the presbyter. In joining with the bishop and the church in reciting the Creed of Nicaea, a presbyter affirms their calling to be creedal in teaching, proclamation and catechesis.
I note that in the 1979 Prayer Book, the importance of the bishop's call "to guard the faith, unity, and discipline of the Church" is highlighted after the Examination when the bishop-elect initiates the recitation of the Nicene Creed by saying, "We believe in one God" (BCP, pp. 517, 519). The entire gathered assembly then affirms the faith of the Church by saying the Creed in unison.
The order is different in the rite for ordaining priests. As in the Sunday Eucharistic liturgy, the Nicene Creed is said or sung immediately after the Sermon and before the Examination. But the fact that the Nicene Creed is a fixed part of the ordinal goes to Catholicity and Covenant's point: presbyters are called to be creedal by sharing in the ministry of safeguarding the Church's Christological and Trinitarian confession along with the bishops.
I would go a bit further than Catholicity and Covenant to add that deacons and laypersons are also called to be creedal. Like bishops and presbyters, deacons have also promised "to conform to the doctrine, discipline and worship of the Episcopal Church" (BCP, p. 538). The fact that the Nicene Creed is a fixed part of the Eucharistic liturgy on Sundays and other Major Feasts places that statement of faith very clearly within the Episcopal Church's doctrine, discipline, and worship. Like bishops and presbyters, deacons are called to conform their teaching and proclamation to this creedal norm.
And as I've written before, lay Episcopalians are bound by vows, too. I note that the first half of the Baptismal Covenant is the Apostles' Creed, and the first promise we make is "to continue in the apostles' teaching and fellowship." In the Baptismal Covenant, all Episcopalians affirm that the faith of the Church articulated by the Apostles' Creed (and, I believe, by extension and amplification in the Nicene Creed) is the norm of belief against which our own personal, individual beliefs are measured and found more or less adequate. And we are promising to conform our believing and witness to this creedal norm.
There are no exceptions. All Episcopalians - bishops, presbyters, deacons and laypersons - are called to be creedal.