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 resurrect the victims of the Snap. 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 Avengers Compound 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 resurrecting the victims of the Snap, at the cost of his right arm being severely charred from the Stones' power and the glove being scorched and damaged.
After recovering from the attack, Hawkeye saw the Nano Gauntlet buried underneath rubble and managed to recover it. After Hawkeye saw that Outriders were after the gauntlet, he ran down the tunnels with it and was able to get out of the tunnels, safely securing the gauntlet.
Exhausted, Hawkeye laid down and saw Nebula arrive. He gave her the gauntlet, unaware that it was actually an alternate version of Nebula. The alternate version of Nebula contacted Thanos to inform him that she had the gauntlet, but she was eventually killed by the original timeline version of Nebula, enabling Hawkeye to reclaim the gauntlet.
As Hawkeye carried the Nano Gauntlet with him as a battle waged, he asked Captain America what he should do with the gauntlet, and was instructed to bring it to Luis' Van. Hawkeye was assisted by Black Panther who took it from him, and then gave it to Spider-Man. Spider-Man secured the gauntlet, until he gave it to 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. Briefly subdued by Captain Marvel, Thanos temporarily removed the Power Stone from the gauntlet to knock her out.
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 armor, who proceeded to use the Stones to destroy Thanos' army, the Black Order, and even Thanos himself, with the Nano Gauntlet still on Thanos' hand.
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 could not contain the stones' power as well as the Infinity Gauntlet could, likely because it was not constructed from a material strong enough to safely channel the power of the stones. 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 if they did not have the physical capability to handle the stones' power, as was the case with Hulk or worse, fatal damage, as was the case with 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 Iron Man armors constructed from nanotechnology. Iron Man used this to his benefit when he transfered the nanites containing the Infinity Stones from the Nano Gauntlet into his armor, merging its nanites with his suit and safely transferring the stones between them.