Nyx is a common Plane — Theros card from March of the Machine Commander (MOC), collector number 61. Current market price: $2.49, TCGplayer market prices via Scryfall.
Nontoken creatures are enchantments in addition to their other types. Constellation — Whenever an enchantment you control enters, you gain 1 life. Whenever chaos ensues, choose a color. Add an amount of mana of that color equal to your devotion to that color.