Does Nick Fury from The Avengers age? I've discovered that the comic book version uses the Infinity Formula to stay young so I'm curious to know if the MCU version does so also.
There is no mention or indication of any youth-giving formula or delayed ageing of Nick Fury in any MCU media.
He's always played by the same actor, with no age-changing make-up effects, and the in-universe passage of time is basically aligned with out of universe (so the character's ageing is matched by the actor's).
In Captain Marvel, set in 1995, he is digitally de-aged to roughly how the actor looked in 1995. This further supports the proposition that Fury ages exactly the same as a regular human male.
In the comics, Nick Fury has been established as being active during World War II (he first appeared as the title character in Sgt Fury and his Howling Commandos, a few years before the first S.H.I.E.L.D. story).
In 1976, Marvel published Marvel Spotlight 31, (a story by Jim Starlin and Howard Chaykin*) wherein it's established that Nick continued to be an active secret agent despite his advancing years (admittedly, he probably should have only been in his 50s by that point) by using an experimental drug/potion/medicine called the Infinity Formula (no relation to the Infinity Gems or Gauntlet, other than the writer - maybe Starling just likes the word "Infinity").
This story was mostly ignored for years - possibly with good reason, as multiple members of Fury's Howling Commandos team also became S.H.I.E.L.D. agents, most notably Timothy "Dum-Dum" Dugan. It's been referred to more in the past 20 years or so, as Fury reached the point where he'd at be at least in his 70s. And Dum-Dum, the only other prominent Commando left,
was recently determined to be a series of LMDs with a single consciousness.
However, to the best of my recollection, while Marvel has established that there was a wartime unit named the Howling Commandos (seen both in the first Captain America movie, and in season 2 of Agent Carter), Fury has not been established as being a part of this unit at that time.
Without such a time to a specific point in time to make him seem inexplicably young, there's been no reason to bring the Infinity Formula into the MCU and Nick's backstory to date.