Naruto would likely be extremely confused at first. He has always idolized his father, and to have Minato do such a thing would shatter his perception. He'd probably try to talk to Minato, ask him why he's doing it.
One reason could be for protection. Maybe in the fanfiction, there are powerful enemies targeting Naruto's chakra specifically. Minato, as his father, seals it away to keep Naruto safe from those who would misuse his power.
Perhaps Minato has been corrupted by power. In the fanfiction world, he might have come across some source of power that has twisted his mind. By sealing Naruto's chakra, he could be trying to take that power for himself. It could also be related to some prophecy that he misinterprets. He thinks sealing Naruto's chakra is the key to saving the world, but in reality, it's the opposite.
It could make his friends more protective. Since Naruto is in a weakened state without his full chakra, his friends might be more concerned about him and try to keep him out of dangerous situations.
It can strengthen Naruto's relationship with his family on a spiritual level. Even though they are sealed within him, he might feel a closer bond to his parents. This could make him more confident in his identity as the son of Minato and Kushina.
There could also be a shift in the power balance within the ninja world. Other villages might see Konoha as weakened due to Minato's self - sealing and might take advantage of the situation, leading to more conflicts and power struggles among the villages.
One of the main similarities is their self - sacrifice. Minato sacrificed himself to save the village and his son. Naruto has also shown that he is willing to put himself in harm's way for the greater good. He's always the first to jump into a dangerous situation if it means protecting those he loves. Another aspect is their leadership qualities. Minato was a great leader as Hokage, and Naruto has developed into a great leader as well, inspiring those around him.
Well, it could be that Naruto discovers an ancient artifact that contains Hashirama's chakra. When he touches it or unlocks its power in some way, the chakra gets transferred to him. For example, the artifact might be hidden in a secret location and Naruto stumbles upon it during one of his adventures.
Perhaps the origin of the chakra chains lies in Naruto's connection to the tailed beasts. Since he has a unique bond with the nine - tailed fox, the chakra chains might be a manifestation of that bond, combined with his own latent Uzumaki powers. It's possible that as he grew stronger and his understanding of chakra deepened, this ability was awakened.
Minato's presence can have a huge impact. He can act as a mentor, teaching Naruto things he never knew about his family and heritage. His wisdom and skills can inspire Naruto to reach new heights in his training and ninja development.