There are different versions of the Orphic take on creation, but all deal with the World Egg, also known as the Cosmic Egg. One begins with Khronos alone.
From the Orphic mystery cult, Khronos creates an egg that Phane's, father and mother of Nyx, emerges from.
"The cosmic egg is featured in yet another Greek creation myth, that of the Orphic mystery cult of the seventh century B.C.E. In this account, Time (personified as Chronus [Kronos]) creates a silver egg that gives birth to Phanes, the androgynous creator of the universe who possesses two pairs of eyes and magnificent wings of gold. Phanes, whose dual sexual nature rests in the origin of all life, represents the state of oneness that exists before the unfolding of differentiation occurs. The creator's name, which means 'shining one' or 'the revealer', signifies the appearance of light within the cosmos, and when Phanes then creates his daughter Nyx (Night), the process of differentiation begins. Together, Phanes and Nyx give birth to Gaea [Gaia] and Uranos [Ouranos], the Greek gods of earth and sky, and thus the entire universe is engendered by their union."
Sometimes there is a slight variation to how Phanes came to be, but still, it remains an act through one being instead of two.
"As Hesoid had extended the Homeric series of gods by prefixing the dynasty of Uranos to the of Kronos, so the Orphic theogony lengthened it still further. First came Chronos (Khronos), or Time, as a person, after him Æthêr (Aither) and Chaos, out of whom Chronos (Khronos) produced the vast mundane egg. Hence merged out of the process of time the first-born god Phanês, or Mêtis, or Hêrikapæos, a person of double sex, who first generated the Kosmos, or mundane system, and who carried within him the seed of the gods. He gave birth to Nyx, by whom he begat Ouranos and Gæa; as well as Hêlios and Selêne."
There is another one where Khronos and Ananke create the world egg together. This is from Orphic Argonautica 12.
"First (I have sung) the vast necessity [Ananke] of ancient Chaos [Khaos],
And Cronus [Khronos], who in the boundless tracts brought forth
The Ether [Aither], and the splendid and glorious Eros [Phanes] of a two-fold nature,
The illustrious father of night [Nyx], existing from eternity.
Whom men call Phanes, for he first appeared."
In accordance to Damascius, the most common and familiar Orphic theology is that Khronos was the first principle. He produced Aether, Khaos and the World Egg. The World Egg contained the Triple God. When hatched, it produced Phanes who had two other aspects Erikepaios and Metis.
From Orpheus by George Robert Stow Mead, there is text about "The Karmic Ruler of the Universe".
"Damascius further tells us in the same place that, according to Heironymus and Hellanicus, the Orphic theogony described the third principle symbolically as being 'a Dragon naturally endowed with the heads of a Bull and a lion, but in the middle having the countenance of the God himself.' This power was portrayed with golden wings and denominated Time [Kronos] and Hercules [Herakles]. It was the Karmic Ruler of the Universe, for 'Necessity [Ananke] resides with him, which is the same as Nature [Phusis], and incorporeal Adrastia, which is extended throughout the universe, whose limits she binds in amicable conjunction.'"
Now that that is taken care of, we can go on to Nyx. In Orphic Rhapsodic Theogony Nyx holds great power. As Orpheus and Greek Religion: A Study of the Orphic Movement puts it, she is a protector and adviser of successive rulers of the Universe. Phanes is the first ruler of the gods in Rhapsodic theogony and his only child is Nyx. He eventually hands over his scepter to Nyx, thus passing on his rulership to her. Orpheus and Greek Religion: A Study of the Orphic Movement tells what becomes of her after this in the Rhapsodies.
"He [Phanes] himself goes into retirement, and all we hear of him is his arrangement described in O.F. 105, according to which he sits in the recesses of the cave of Night [Nyx]. In the middle is Night [Nyx], prophesying to the gods, and at the entrance Adrestaia [Adrasteia] who makes their laws. Phanes sits still and takes no further part in things. Night in her turn hands over the power to her son Ouranos, but unlike Phanes she does not sit back as if her work was done. She continues to exercise great influence, giving oracular advice to her successors, who come to her for help and regard her with awe. This active part, she plays right through the reigns of Ouranos, Kronos and Zeus, during which Phanes is as if he had never been."
Book sources:
Thematic Guide to World Mythology. Lorena Laura Stookey. Greenwood Press. 2004.
History of Greece. Volume 1. George Grote. Adamant Media Corporation. 2001.
Orpheus. George Robert Stow Mead. Theosophical Pub. Society. 1896.
Orpheus and Greek Religion: A Study of the Orphic Movement. Edited by Larry Alderink. Princeton University Press. 1993.
Internet sources:
Sacred-Texts - Orphic Fragments