Perhaps in this fanfiction, Naruto has some sort of special power or transformation that he unlocks just in time to face Orochimaru. It could be related to his Nine - Tails chakra in a new and unique way. He uses this power to break through Orochimaru's defenses and save Hiruzen. Naruto might also use his knowledge of Orochimaru's weaknesses that he has learned either from Jiraiya or from his own past encounters with Orochimaru's minions.
Maybe Naruto is put in a situation where he feels that Hiruzen's way of handling things is the best option. For instance, if there is a major crisis in the village that requires a more traditional and experienced approach, Naruto might choose to act like Hiruzen. Also, he could be influenced by the stories he has heard about Hiruzen and wants to fill his shoes in a way.
Naruto would likely win. Godlike Naruto implies he has extraordinary powers. Naruto has strong chakra reserves, and his signature jutsus like Rasengan are extremely powerful. Also, his ability to quickly adapt in battle gives him an edge over Orochimaru.
He could have the power to instantly heal any injury. His chakra might be so vast that he can create multiple clones without getting tired. Also, he might be able to control the elements in ways that are beyond normal shinobi capabilities.
One possible scenario in a 'Naruto Saves Hiruzen' fanfic could be that Naruto uses his newfound powers. Maybe he has mastered a new jutsu that allows him to turn back time briefly. He then uses this power to go back to the moment when Hiruzen is in danger. Naruto's quick thinking and his never - give - up attitude would be highlighted in such a fanfic.
Perhaps Naruto discovers a prophecy that Hiruzen will be in danger. So, he starts to train extra hard to be able to face whatever threat is coming. When the time comes, he uses his speed, which he has enhanced through rigorous training, to reach Hiruzen before the enemy can land a final blow.
There are quite a few. One such fanfic is 'The Mentor's Wisdom' where Hiruzen imparts his knowledge and skills to Naruto in a detailed and engaging way.
In some fanfics, Naruto might use his new and powerful jutsu that he has mastered over time. Maybe he combines his Sage Mode with the power of the Nine - Tails in a unique way that Orochimaru can't counter. For example, he could use the Nine - Tails' chakra to enhance the range and power of his Sage Mode attacks, and then catch Orochimaru off - guard.
In the fanfiction, Hiruzen might raise Naruto properly by providing a stable living environment. He could ensure Naruto has a decent place to live, enough food to eat, and warm clothes. This basic care is fundamental for Naruto's growth.