Nano-spray paint was a type of spray paint that evaporated a few days after application. Doctor Ragon used the paint to mark-up patients before surgery. In 3 ABY, the bounty hunter Boba Fett, in order not to be recognized, painted his armor black using nano-spray paint.
In 3 ABY, the bounty hunter Boba Fett had a job to do on behalf of Ragon, who allowed him to use nano-spray paint to paint his armor black. Fett joined a fight in the Garkata Fighting Arena against many warriors, including Wyrmen Lictor, a warrior who was valuable to the Kanji Hutts and that Ragon had asked him to kill. Since the Kanji Hutts were powerful, Fett used the paint in order to avoid being recognized, trying to avoid a feud with the Hutts. After killing all his opponents, Fett left the arena and, by the time he arrived back at Ragon's clinic, the paint was no longer on his armor.
Later on, a hologram of Fett's armor painted black was displayed on Nar Shaddaa. When the Jedi Luke Skywalker saw it, he recognized the bounty hunter despite the paint.
Nano-spray paint first appeared in the one-shot comic War of the Bounty Hunters Alpha 1, published by Marvel Comics on May 5, 2021. The comic was written by Charles Soule and illustrated by Steve McNiven and Laura Martin. Prior to the comic's release, it was first pictured in a post published on April 9 of that year on StarWars.com, where McNiven revealed the page breakdowns and sketches of the comic.