system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] What happened before Avengers Infinity War that led to Stark's incorporation of nanotech into his armor? The earlier Iron Man armors are advanced technology, then there's a leap to the armor being almost magical. Is there a reason for this incredible leap in technology?
gpt
Tony Stark's greatest limitation has always been his own lack of motivation and ambition.  For most of his life, he did the bare minimum he could to maintain his position as a billionaire playboy. He improved the Extremis in one night while drunk.  And based on Stane's interactions it doesn't seem like Tony wasn't that involved in the day to day business activities while at the same time the scientist working for Stark Tech, recognized that they weren't on par with Tony.  

It wasn't until Afganistan that Tony gained any focus, but at that time he was only going up against Earth-based threats.  The first few challenges he faced were people using derivatives of his own technology.  He didn't need to innovate that much yet.

The next big push was the Invasion of New York, which showed him that there was a much bigger universe and larger threats.  His reaction was the Ultron Project, this required a significant work but also ended up being a major failure.  This left him back at square one while also his conversations with Thor further convinced him of the need for better weapons.

And this is what leads to the nano-tech, Tony was now focused and eager to create something powerful.  Tony always had the capacity to create nano-tech he just never had the drive to do it.  But, once he had the motivation to sit down for a few months/years creating it wasn't an issue.