While there are many Avengers whose powers rival those of cosmic gods, Thor, the God of Thunder himself, actually named the one Avenger who is basically a god… and this hero-in-question might be the least obvious choice of the bunch.
Thor first came to Earth sometime in the 9th century in order to promote himself as a god worthy of worship. While on Earth, Thor battled numerous villains and monsters (even En Sabah Nur before he became the X-Men villain, Apocalypse), which only gave Thor more credibility as an all-powerful god. However, during the relatively modern era, Loki attacked the Earth with the intention of conquering the planet, and Thor needed the help of some other, more recently developed heroes in order to stop the God of Mischief. It is here when the Avengers were born, and when Thor first met the mortal hero who he would later regard as a god: Tony Stark aka Iron Man.
Thor Thinks Iron Man is Basically a God
In Thor: God of Thunder #3 by Jason Aaron and Esad Ribic, Thor is hunting Gorr the God Butcher in three separate eras of his life: as a young god in the late 800s on Earth, as a moderately experienced god in the present day, and as an old god in the far future. In the past, Thor tried and failed to kill Gorr after tracking the God Butcher to a cave in the area of the world that would become Russia. While Thor failed as a young god, he was determined to not do so again in the present day. Thor decided to go back to that cave to look for a sign of Gorr, as Thor realized that the God Butcher was still very much at large despite centuries of hearing nothing from him. There was just one problem: Thor wasn’t exactly sure where that cave was–it had been a few hundred years, after all. So, Thor recruited the help of Iron Man (more accurately, Tony Stark) to help him find the cave and travel to its location with him before Thor explained that he had to go in alone. As Iron Man flew away a bit deflated by the fact that Thor didn’t want or need his help, Thor told him, “you are as much a god as any immortal I have ever known, Tony Stark” and then asked him for one more favor.
Thor didn’t just need Iron Man to find the cave where he last fought Gorr, but also to fly to Mount Olympus and warn the Gods of Earth of the danger they are in with Gorr on the loose. This means that Thor not only recruited Stark to help him find Gorr, but also to speak to other immortal deities on his behalf. If that’s not the ultimate sign of god-tier respect, then nothing is. But, Thor’s statement here actually has a deeper meaning than just this mission. When looking at everything Iron Man has done throughout the comics, it becomes clear that Tony Stark is about as close as a mortal can be to a god–and that’s not even counting the time Iron Man bathed in the Power Cosmic and actually did become a god. The things Iron Man can do with his suits rival cosmic beings daily, with some of his strongest pieces of armor being his Bleeding Edge armor, Endo-Sym armor, and even the Godbuster armor.
In essence, Thor trusts Iron Man as if he were a fellow god, and Iron Man earned that trust by essentially being a mortal-born god with all the exhibitions of his unparalleled might through his increasingly powerful, god-tier suits. So, while Iron Man is one of the few Avengers with no superpowers, he is still the one Thor admits is basically a god–and for good reason.