Well, it could change a lot. For example, he might be able to prevent some of the tragic events that happened in the original. He could stop the deaths of his comrades like Jiraiya. He could also reshape the ninja world order more quickly, maybe by eliminating the root cause of the shinobi wars directly.
Well, he might use his reality - controlling power to make himself the most powerful ninja instantly. He could also create a world where ninjutsu has no negative side - effects. For instance, no one would go blind from overusing the Mangekyo Sharingan. Or he could make it so that everyone can understand each other's language without any communication barriers in the ninja world.
He could control elements like water, which would allow him to create powerful waterfalls or form water - based defenses. Fire is also a possibility, enabling him to shoot out intense flames. Another type could be earth, where he can manipulate the ground to create barriers or traps.
In some fanfictions, it could be due to a new jutsu he discovers. Maybe during a secret training session in an ancient scroll, he finds a forbidden technique that allows him to control people.
Well, in some fanfictions, Naruto might gain the ability to control nature through intense training with a hermit or some ancient spirit. For example, he could be led to a hidden grove where the essence of nature is concentrated, and by communing with it over time, he gradually unlocks the power to control nature.
Maybe it could be through some sort of magical jutsu. Naruto is known for his unique ninjutsu skills in his own universe. He might have developed a new jutsu that allows him to connect with and control the Hulk's mind. For example, it could be a jutsu that detects and manipulates gamma radiation, which is what created the Hulk. Or perhaps he found a way to use his chakra in a new way to interface with the Hulk's rage - powered form.
Another possibility is that Naruto acquires the ability to control the weather from a powerful artifact. He might stumble upon an ancient relic during one of his adventures. This artifact has the power to control the weather, and once Naruto touches it or figures out how to use it, he gains this extraordinary ability. It could be that the artifact was created by a long - forgotten civilization that had mastered the art of weather manipulation.
It could also have implications for the Hulk himself. Usually, the Hulk is a wild and uncontrollable force. But with Naruto in control, he might be able to be used in more positive ways. The Hulk could be directed to help rebuild instead of just destroy. And from a character development perspective, the Hulk might learn to control his rage better under Naruto's influence, and Naruto might learn new things about power and responsibility from having to control such a powerful being.
In Naruto fanfiction, time control can be used in various ways. For example, a character could use time - control jutsu to go back in time and prevent a tragic event from happening in the Naruto world, like the Uchiha massacre. They might also use it to speed up their own training, spending what seems like months of intense practice in just a few minutes of real - time.