One possibility is that Naruto calls for help. He realizes that dealing with Kaguya alone could be too dangerous. So he might use his shadow clones to go and get his friends like Sasuke, Sakura and Kakashi. Together they can figure out what to do with Kaguya and the mystery of the lab.
In this fanfiction scenario, Naruto could also discover that there is some sort of dark magic or experiment that is keeping Kaguya chained. He may then try to break the chains using his own chakra or some special jutsu. But he has to be careful not to accidentally release Kaguya's full power which could cause chaos all over again.
Well, Naruto might first try to free Kaguya. He is a hero after all and doesn't like to see anyone chained unjustly. But he would also be very cautious because Kaguya is extremely powerful and was once a great threat. He could try to communicate with her to understand why she is chained there in the first place.
Well, Naruto would probably immediately try to free her. He's the kind of person who can't stand seeing someone in distress. He might use his ninja skills to break the chains quietly if he's worried about enemies nearby. Then he'd likely ask her who she is and how she ended up there.
Another scenario could be that Naruto discovers a hidden chamber in the lab. Inside, there are test subjects that Orochimaru was using for his immortality experiments. Naruto feels sympathy for them and tries to rescue them. However, he has to figure out how to deal with the various traps and security measures in the lab first. He might call for help from his friends like Sakura or Kakashi to assist him in this difficult task.
Naruto would feel a sense of responsibility. He might think that it's his duty to do something about it. He could start by examining the chains to see if there is any way to break them. He would also be on high alert because he doesn't know if this is some sort of trap. He would be thinking about all the possible consequences of his actions and how it could affect the world around him.
He might discover some long - lost jutsu. Ancient labs could hold secrets to powerful ninja techniques that have been forgotten over time. Maybe he'll find scrolls with unique chakra - based abilities or old - fashioned weapons with special powers.
One possibility is that Naruto's chakra nature could change completely. Since Kaguya had unique chakra, Naruto might develop new jutsu that are a blend of his own and Kaguya's abilities. For example, his Rasengan could gain the power to not only attack but also to heal, as Kaguya had some form of life - giving power. Also, his connection to the tailed beasts could be enhanced in unexpected ways, allowing for better communication and cooperation with them.
He might discover some new and powerful jutsu hidden there. Maybe it's a lab created by an ancient ninja clan that was lost to history.
In a fanfiction scenario where Naruto finds a lightsaber, he could potentially incorporate it into his fighting style. He's always been creative in combat. He might use his ninja skills like speed and agility along with the lightsaber's unique capabilities. For example, he could use his shadow clone jutsu and have his clones all wield the lightsaber in different ways to confuse his enemies.
He might meet someone who is also after the scythe. This could lead to a conflict or an alliance. If it's an enemy, Naruto will surely fight to keep the scythe. But if it's someone who can help him understand the scythe better, they could team up and go on adventures together.
Another possibility is that the robot is from a future where ninjas no longer exist. It could be sent back in time for some reason, and Naruto is the key to its mission. The robot might need Naruto's help to change something in the past to ensure a better future. Naruto, being the hero he is, would likely take on this challenge without hesitation, leading to a whole series of exciting adventures.
Naruto could find a book that tells the story of a great hero who was just like him, full of energy and a desire to protect. This could inspire him to new heights. He might also accidentally trigger a trap or a hidden mechanism in the library while exploring, leading to an adventure filled with challenges and puzzles to solve.