Is acceptance of the Trinity & Nicene Creed the acceptance
that Jesus is a human God?
No.
Quite simply because nowhere in the Nicene Creed does it say that Jesus is a “human God” and there IS NO “Trinity Creed”. There is a Doctrine of the Trinity, which is not a creed, and can be expressed in many different ways, but at its core just claims that the “Father” from the Gospels and “Jesus” and the “Holy Spirit” are all “One God”.
The Nicene Creed actually states (and those that believe it affirm) the following:
We believe in one God,
the Father almighty,
maker of heaven and earth,
of all things visible and invisible.
And in one Lord Jesus Christ,
the only 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 the same essence as the Father.
Through him all things were made.
For us and for our salvation
he came down from heaven;
he became incarnate by the Holy Spirit and the virgin Mary,
and was made human.
He was crucified for us under Pontius Pilate;
he suffered and was buried.
The third day he rose again, according to the Scriptures.
He ascended to heaven
and is seated at the right hand of the Father.
He will come again with glory
to judge the living and the dead.
His kingdom will never end.
And we believe in the Holy Spirit,
the Lord, the giver of life.
He proceeds from the Father and the Son,
and with the Father and the Son is worshiped and glorified.
He spoke through the prophets.
We believe in one holy catholic and apostolic church.
We affirm one baptism for the forgiveness of sins.
We look forward to the resurrection of the dead,
and to life in the world to come. Amen.
The Doctrine of the Trinity is more clearly seen within the Athanasian Creed:
That we worship one God in trinity and the trinity in unity,
neither blending their persons
nor dividing their essence.
For the person of the Father is a distinct person,
the person of the Son is another,
and that of the Holy Spirit still another.
But the divinity of the Father, Son, and Holy Spirit is one,
their glory equal, their majesty coeternal.
What quality the Father has, the Son has, and the Holy Spirit has.
The Father is uncreated,
the Son is uncreated,
the Holy Spirit is uncreated.
The Father is immeasurable,
the Son is immeasurable,
the Holy Spirit is immeasurable.
The Father is eternal,
the Son is eternal,
the Holy Spirit is eternal.
And yet there are not three eternal beings;
there is but one eternal being.
So too there are not three uncreated or immeasurable beings;
there is but one uncreated and immeasurable being.
Similarly, the Father is almighty,
the Son is almighty,
the Holy Spirit is almighty.
Yet there are not three almighty beings;
there is but one almighty being.
Thus the Father is God,
the Son is God,
the Holy Spirit is God.
Yet there are not three gods;
there is but one God.
Thus the Father is Lord,
the Son is Lord,
the Holy Spirit is Lord.
Yet there are not three lords;
there is but one Lord.
Just as Christian truth compels us
to confess each person individually
as both God and Lord,
so catholic religion forbids us
to say that there are three gods or lords.
The Father was neither made nor created nor begotten from anyone.
The Son was neither made nor created;
he was begotten from the Father alone.
The Holy Spirit was neither made nor created nor begotten;
he proceeds from the Father and the Son.
Accordingly there is one Father, not three fathers;
there is one Son, not three sons;
there is one Holy Spirit, not three holy spirits.
Nothing in this trinity is before or after,
nothing is greater or smaller;
in their entirety the three persons
are coeternal and coequal with each other.
So in everything, as was said earlier,
we must worship their trinity in their unity
and their unity in their trinity.
Nowhere in either of these does it claim that Jesus is a human God, so those that affirm these Creeds do not claim that Jesus is a human God.