How to sort Marvel Cinematic Universe hero movies into a chronological order?

Chronology order of Marvel Cinematic Universe (Own by Disney) is as follows :-

20th Century

• Captain America: The First Avenger
• Agent Carter
  • Now is Not the End
  • Bridge and Tunnel
  • Time and Tide
  • The Blitzkrieg Button
  • The Iron Ceiling
  • A Sin to Err
  • Snafu
  • Valediction
• Marvel One-Shot: Agent Carter

21st Century

• Iron Man
• Iron Man 2
• The Incredible Hulk
  • Marvel One-Shot: A Funny Thing Happened on the Way to Thor's Hammer
• Thor
  • Marvel One-Shot: The Consultant
• Captain America: The First Avenger (ending)
• The Avengers
  • Marvel One-Shot: Item 47
• Iron Man 3
• Marvel One-Shot: All Hail the King
• Agents of S.H.I.E.L.D. (season one)
  • Pilot
  • 0-8-4
  • The Asset
  • Eye-Spy
  • Girl in the Flower Dress
  • FZZT
  • The Hub
• Thor: The Dark World
• Agents of S.H.I.E.L.D. (season one)
  • The Well
  • Repairs
  • The Bridge
  • The Magical Place
  • Seeds
  • T.R.A.C.K.S.
  • T.A.H.I.T.I.
  • Yes Men
  • End of the Beginning
• Captain America: The Winter Soldier
• Agents of S.H.I.E.L.D. (season one)
  • Turn, Turn, Turn
  • One Door Closes (flashbacks)
  • Providence
  • The Only Light in the Darkness
  • Nothing Personal
  • Ragtag
  • Beginning of the End
• Guardians of the Galaxy
• Agents of S.H.I.E.L.D. (season two)
  • Shadows
  • Heavy is the Head
  • Making Friends and Influencing People
  • Face My Enemy
  • A Hen in the Wolf House
  • A Fractured House
  • The Writing on the Wall
  • The Things We Bury
  • Ye Who Enter Here
  • What They Become
  • Aftershocks
  • Who You Really Are
  • One of Us
  • Love in the Time of HYDRA
  • One Door Closes
  • Afterlife
  • Melinda
  • The Frenemy of My Enemy
  • The Dirty Half Dozen
• Avengers: Age of Ultron
• Agents of S.H.I.E.L.D. (season two)
  • Scars
  • S.O.S. Part One
  • S.O.S. Part Two

(Source:marvelcinematicuniverse.wikia.com)

Note:- Marvel One-Shots are a series of direct-to-video short films produced by Marvel Studios. They are included as special features in the MCU films' Blu-ray and digital distribution releases.

This is difficult because many of the movies/episodes overlap. Most notable is "Fury’s Big Week" which is the name for the week in which "The Incredible Hulk", "Iron Man 2", and "Thor" all occurred simultaneously.

There are scenes in "Thor: The Dark World" dating back to 2987 B.C. even though the majority occurred in 2012.

Similarly, "Captain America: The First Avenger" shows scenes from 1933 upto 2011 despite taking place mostly in 1943-1945

Here is the complete list of events with more detail than anyone needs

This website gets updated whenever a new show / film is released, meaning it will always be up-to-date.

As of March 2021:

• Captain America: The First Avenger – takes place during WWII
• Captain Marvel – occurs in 1995
• Iron Man – takes place in 2008
• Iron Man 2 – takes place after Iron Man
• The Incredible Hulk – time unspecified, pre-Avengers
• Thor – events occur six months before Avengers
• The Avengers – takes place in 2012
• Iron Man 3 – takes place six months after The Avengers
• Thor: Dark World – post-Avengers, pre-Ultron
• Captain America: Winter Soldier – post-Avengers, pre-Ultron
• Guardians of the Galaxy Vol. 1 – sometime in 2014
• Guardians of the Galaxy Vol. 2 – set after Guardians
• Avengers: Age of Ultron – occurs in 2015
• Ant-Man – takes place in 2015
• Captain America: Civil War – post-Ultron, pre-Infinity War
• Black Widow – takes place right after Civil War
• Spider-Man: Homecoming – post-Civil War, pre-Infinity War
• Doctor Strange – takes place in 2016
• Black Panther – takes place in 2017
• Thor: Ragnarok – post-Ultron, pre-Infinity War
• Avengers: Infinity War – occurs in 2017
• Ant-Man and The Wasp – ambiguous, but fits nicely between Infinity War and - - Endgame (so around 2017)
• Avengers: Endgame – starts in 2017, finishes in 2022
• WandaVision – three weeks after Endgame
• The Falcon and the Winter Soldier – around six months after Avengers: Endgame
• Spider-Man: Far From Home – set eight months after Endgame
• Loki – post-The Avengers in 2012, but best watched after Endgame
• What If...? season 1 – technically, this spans the entire multiverse, but it's best watched after Endgame
• Shang-Chi and the Legend of the Ten Rings – set in the 'present' day of the MCU, i.e. 2022
• Eternals – set in the 'present day' of the MCU, although it travels through 7,000 years of human history
• Spider-Man: No Way Home – mostly set in the MCU's 'present' day, but its first 10 minutes take place right after Far From Home
• Hawkeye – one year after Endgame

My guess is that the producers/movie studio (correctly) set things up so that if you watched the movies as they were released, you'd be watching them in the 'correct' order.

Hence, the Wikipedia list by order of US release date is probably what you want to use.

In cases where the release dates were close to each other, it probably doesn't matter too much which you watch first. E.g. from what I recall, Iron Man (released in May 2008) and Incredible Hulk (June 2008) did not seem to have any references to each other, so it is probably 'no big deal' to watch either one before the other.

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