Nut held up by her father, Shu. Geb can be seen reclining on the ground. From "Egyptian Mythology" by Veronica Ions.

Nut, identified only by the hieroglyphs above her head, on the ceiling of a recently discovered tomb. Taken by the renowned Egyptologist, Dr. Hawass. (http://www.drhawass.com/photoblog/image-goddess-nut-tt11)

A note on Incest

In ancient Egypt, incest was a very common occurrence in both mythology and royal tradition. Just as the gods married and procreated with their siblings and parents, so did the pharaohs of ancient Egypt. The purpose of this was to keep the royal bloodlines pure. While it may come as shocking and revolting to modern readers, incest was really quite commonplace in the ancient world.

Nut: Other Associations

Nut is associated with other worldly things. She and her daughter Isis are equated with the sycamore tree. Many coffins were constructed from sycamore wood for even more of Nut’s protection. Nut is also identified with the number nine, mainly because of her inclusion in the Heliopolitan ennead: Atum, Shu, Tefnut, Geb, Nut, Osiris, Isis, Set, and Nephthys. Another, more obvious connection is with the color blue (irtiu/khesbedj). Ancient Egyptians held that the color blue symbolized water and the heavens, but, since water can also be represented by green, mainly the heavens. Yellow is considered another heavenly color, mainly of the sun and stars. 

A note on Cosmogonies

In the ancient Egyptian tradition, there are four central cosmogonies: the Heliopolitan cosmogony, the Memphite cosmogony, the Hermopolitan cosmogony, and the Theban cosmogony. While these are the primary accounts of mythological tradition, there are countless other cosmogonies that have not yet been named. I, as a very opinionated, albeit novice, scholar of Ancient Egyptian culture, prefer the Heliopolitan cosmogony.

Nut: Guardian of the Dead

The goddess Nut plays a very important role in the order of the world. Every single morning, she gives birth to the sun. This newborn, resurrected sun is known as the god Khepri. He is often represented as a scarab beetle. The resulting blood turns the sky pink as the sun rises. When night begins to fall, it is said that Nut swallows the sun, so that he might be born again at dawn. Because of her affiliation with Khepri, Nut is also associated as the Protector of the Dead. It is held that the dead become stars on her body. For this reason, she is often painted on the inner lid of sarcophagi, in hopes that the dead will be protected.

A sarcophagus depicting Nut.
(http://brunelleschi.imss.fi.it/galileopalazzostrozzi/object/SarcophagusLidPortrayingTheGoddessNut.html)

A picture from "Egyptian Mythology" by Veronica Ions.