Short answers, pulled from the story.
Astronomers captured images of Nix on the 15th of May 2005 using the Hubble Space Telescope. The discovery team announced the findings publicly on the 31st of October 2005 after confirming data from archival images dating back to 2002.
The International Astronomical Union approved the name Nix on the 21st of June 2006 in IAU Circular 8723. The name honors Nyx, the Greek goddess of darkness who is also the mother of Charon, while the spelling avoids confusion with asteroid 3908 Nyx.
Nix tumbles chaotically due to gravitational interactions with both Pluto and Charon rather than keeping one side facing its parent planet. At the time of the New Horizons flyby, it rotated retrograde with a period of 43.9 hours and an axial tilt of 132 degrees.
Scientists officially named two craters on Nix through the International Astronomical Union on the 2nd of September 2021. The largest crater measures roughly 27 kilometers across and is called Gleti, while the second feature spanning approximately 18 kilometers is named Metztli.
Nix orbits the Pluto-Charon barycenter at a distance between Styx and Kerberos with an orbital period of 24.8546 days. A 3:2 orbital resonance exists between Nix and Hydra, and another relationship forms a 9:11 resonance with Styx.