The phrase "a single nature" is correct and usable in written English.
It can be used in contexts discussing characteristics, qualities, or the essence of something, often in philosophical or theological discussions.
Example: "In many philosophical debates, the concept of a single nature is often contrasted with dualism."
Alternatives: "one nature" or "a unified nature".
He tries on a range of different identities: "In seeking one's identity it should come as no surprise to unearth more than a single nature".
Athenagoras adduced the first rational apologetic for God's simultaneous unity and trinity by suggesting multiple persons in a single nature and potency.
The theologians of Alexandria generally held that the divine and human natures were united indistinguishably within a single nature, though the questions of how they were related and whether in fact they were distinguishable were not settled immediately.
Opposed to this dyophysitism, or two-nature doctrine, the Coptic and Ethiopian churches held that the human and divine natures were equally present through the mystery of the Incarnation within a single nature.
What makes one point in an object different from another point, if the object is of a single nature?
Any thing that genuinely is cannot be subject to coming-to-be or passing-away, must be of a single nature, and must be complete, in the sense of being unchangeably and unalterably what it is.
They have a single-nature relationship such that, if one did not exist, neither could the other, just like being conditioned and impermanent".
At the Council of Chalcedon (451) and in a letter to the Eastern Roman emperor Leo I in 457, he refuted the heterodox monophysite tenet of a single, divine nature in Christ by maintaining Christ's dual (human and divine) natures.
Art in America had a single theme: nature".
A learned lawyer, John composed several tracts against Monophysite teaching, a heretical doctrine maintaining a single, divine nature in Christ subsuming his humanity.
The electron diffraction (ED) pattern of the particle indicated a single crystal nature.
