The Nano Gauntlet was a glove made of nano-technology created by Tony Stark, Bruce Banner, and Rocket Raccoon in 2023. It was designed to contain and allow the user to channel the powers of the Infinity Stones in a manner similar to the Infinity Gauntlet, although the effects of wielding it were far more damaging to the user than the Infinity Gauntlet was.
The Nano Gauntlet was created by Tony Stark, Bruce Banner, and Rocket Raccoon to allow the Avengers to utilize the six Infinity Stones they had gathered during their Time Heist to bring the snapped victims back. Once Stark inserted each of the Stones into the Nano Gauntlet, the Avengers debated over who should use the gauntlet. With Thor deemed unfit to perform the action, it was decided that Hulk would wield it since the stones' energy contained gamma radiation.
When wielded by Hulk, the gauntlet reshaped itself to fit his hand. The Avengers deployed defenses to withstand any potential unprecedented consequences caused by the Stones' power. As one final defense, F.R.I.D.A.Y. locked down the entire New Avengers Facility with the Barn Door Protocol. Banner then equipped the gauntlet and the six Stones' power surged through his arm as he struggled to put his finger and thumb together. Eventually, he succeeded in snapping his fingers and reversed the Snap, at the cost of his right arm being severely charred from the Stones' power and the glove being scorched and damaged. 
When Thanos came to 2023 from 2014 and attacked the New Avengers Facility, the Nano Gauntlet was lost in the explosion. However, Hawkeye managed to recover it while escaping from Outriders on his trail.
Exhausted, Hawkeye enabled Nebula to take the gauntlet, unaware that it was actually her 2014 counterpart who was still loyal to Thanos. This version of Nebula contacted her father to inform him she had completed her mission, but was eventually killed by her future self and Gamora, enabling Hawkeye to reclaim the gauntlet.
As the battle between the Avengers and Thanos' armies waged, Hawkeye asked what to do with the Nano Gauntlet, so he was instructed to bring it to Luis' Van. The Nano Gauntlet was passed from hero to hero, including Black Panther, Spider-Man, and eventually Captain Marvel.
Nevertheless, Thanos fought his way through Captain America, Thor, Iron Man, and Captain Marvel and eventually retrieved the gauntlet, donning it and attempting to keep it equipped in order to perform his new plan; to erase the entire universe and start a new one from scratch. Briefly subdued by Captain Marvel, Thanos temporarily removed the Power Stone from the gauntlet to get rid of her.
Thanos then put the Power Stone back onto the gauntlet and prepared to snap his fingers, only to be stopped by Iron Man. Thanos repelled him and, claiming he was inevitable, snapped his fingers expecting the universe to perish. Much to his dismay, however, he suddenly realized that the Infinity Stones had been stripped from the gauntlet and onto Stark's own armor, who proceeded to use the Stones to destroy Thanos' army, the Black Order and even Thanos himself. With the gauntlet still equipped, when Thanos faded away into nothingness, the Nano Gauntlet did so as well.
Like the Infinity Gauntlet, the Nano Gauntlet is capable of channeling the power of all the Infinity Stones at once, granting whoever wields it near-omnipotence. However, while the Nano Gauntlet was made of extremely resilient nanotechnology, much like Tony Stark's Mark LXXXV armor, it cannot contain the stones' power as well as its predecessor could. As such, simply attempting to wield the Stones simultaneously would cause their collective energies to leak from the gauntlet and begin to severely wound the user, as was the case with Hulk and Iron Man.
Due to its nanotechnology, the Nano Gauntlet can shift its nanites around and morph itself to accommodate users of different arm sizes. It can even seemingly repair itself, as the gauntlet appeared less damaged by the time Thanos acquired it. The Nano Gauntlet's nanites can also be transferred into different Iron Man armors made of nanotechnology, as Iron Man had used this to transfer the nanites containing the Infinity Stones into his armor, therefore merging its nanites with his suit and safely transferring the stones between them.