He might gain a more powerful form of Rasengan, like a Rasengan that can change its shape and properties according to the situation. Maybe he has better control over his Nine - Tails chakra and can use it in more creative ways without losing control.
After Kurama's death, Naruto faced new challenges. His chakra reserves were reduced, but he continued to guide and inspire the younger generation of ninjas. He also had to adapt his fighting strategies without Kurama's immense power.
Well, he might have enhanced physical strength. Since Kurama is involved, Naruto could potentially have better control over chakra, which would boost his combat abilities significantly. For example, his Rasengan could be more powerful and easier to form.
Well, in some fanfics, Naruto's death could be like a sacrifice that unlocks some hidden or ancient power. Maybe his death releases a special chakra that was locked within him, and this chakra then transforms into new, more powerful abilities. It could also be that his death is part of a prophecy, and upon his death, a deity or some other powerful entity grants him powers as a reward for his selfless act of sacrificing himself.
Well, Kurama might train Naruto by teaching him how to better control and access chakra. Since Kurama has a vast amount of chakra, it could show Naruto unique ways to harness and use it. For example, it could guide Naruto in creating more powerful and complex jutsu by using their combined chakra in a more efficient way.
The Kurama Brothers could be entities that have a similar origin to Kurama. They might have been part of the same chakra - based creation in the Naruto universe. They could possess some of Kurama's traits like great power and a connection to the natural energy in the world. They are often depicted as having their own personalities, with one being more hot - headed and the other more calm and calculating. Their relationship with Naruto usually involves them using their powers and knowledge to help Naruto grow as a ninja and a person. They might also have their own goals and motives that are intertwined with Naruto's journey.
One possible new power could be the power to absorb and use any chakra, regardless of its origin. This would make him extremely powerful as he could draw from the chakra of his enemies or even from natural sources like the sun or the earth. He could also gain the power of telepathy on a large scale, being able to communicate with anyone in the world or even across different dimensions. Additionally, he might obtain the power of instant teleportation to any place he desires, which would give him a huge advantage in battles and travels.
For Naruto, it would be a whole new experience. He'd be constantly trying to communicate with the mecha Kurama, learning its quirks. Shikamaru might be the one thinking about the strategic uses of mecha Kurama in battle. He'd be coming up with plans on how to best utilize it. As for Kurama, he could be in an internal struggle. Part of him would want to stay relevant in Naruto's battles, while another part would be curious about this new mechanical version of himself and how it could help Naruto in the long run.
Kurama might become angry at first. He's a powerful being and being neglected would likely wound his pride. He could start causing some minor disruptions inside Naruto, like making it harder for Naruto to access his chakra.