One possible plot could be that Naruto, after becoming Hokage, decides to form an international army to combat a new and powerful threat that endangers all the ninja villages. This army would consist of ninja from different villages who have put aside their old rivalries under Naruto's leadership.
Sakura could be a leader. She has strong medical ninjutsu skills and is also a very capable fighter. She could lead the medical unit in Naruto's army, taking care of the injured and also providing strategic advice based on her intelligence. Another possibility is Shikamaru. He is known for his brilliant strategic mind. He could be in charge of planning the army's movements, setting up traps, and devising battle plans to outwit the enemy.
Maybe Naruto creates the robot army as a way to bridge the gap between the ninja villages. He uses them for peaceful purposes like construction and rescue operations at first. But then, a rogue group tries to steal the robots and use them for evil, so Naruto has to fight to protect his creation. Well, in this fanfiction, the robots could be powered by chakra, which gives them an interesting twist. They might also be able to learn ninja techniques from Naruto and the other ninjas, making them a formidable force not just in terms of brute strength but also in combat skills.
Well, he might use his powerful jutsu like the Rasengan. He could also summon his toads to help him out in the battle against the army. Maybe he uses his shadow clone technique to confuse the enemy and then strike them when they're vulnerable.
Well, he might start by using his charisma. Naruto has always been good at making friends. He could reach out to old allies from his village, like Shikamaru and Choji. Also, he might convince some of the outcast ninja who have been mistreated in other villages to join him. His reputation as a hero who saved the world would surely attract a lot of people.
Perhaps it's for exploration. Naruto is always curious about the world outside. The robots can be sent to explore dangerous or uncharted areas where it might be too risky for humans to go. They can collect information and report back to Naruto.
Maybe Naruto has some knowledge from an unexpected source. For example, he could have met a wandering inventor who taught him the basics of robotics. With his determination and quick learning ability, he then starts building the robot army. He might also use his chakra in some unique way to power or control the robots.
Well, Naruto himself would probably be really excited. He'd be running around the military base, trying to make friends with everyone. His positive attitude might initially seem out of place in the strict military environment but could also start to change the atmosphere, making it more lively.
Well, obviously Naruto's friends like Sasuke, Sakura, and Shikamaru could be part of the army. Sasuke with his powerful Sharingan and combat skills, Sakura with her medical ninjutsu and newfound strength, and Shikamaru with his strategic mind. Also, ninja from other villages like Gaara from the Sand Village, who has his own unique abilities and a bond with Naruto, would likely be in the army.