While there's no definitive answer, artists and writers often depict Nyx with:
* Black hair: This aligns with the darkness associated with her and her role as the personification of night.
* Dark blue hair: This color echoes the night sky and the depth of the cosmos, adding a sense of mystery and power.
* Purple hair: Purple is often associated with royalty and magic, fitting for a powerful goddess.
Ultimately, the color of Nyx's hair is open to interpretation. You can choose to imagine her with any color you like, as long as it reflects her mysterious and powerful nature.