In a fanfic, they could start off as strangers and gradually become friends. Maybe Nunnaly gets lost in the Naruto world and Naruto finds her. He takes her under his wing. As they spend time together, they start to understand each other's strengths and weaknesses. This could lead to some interesting adventures, like facing off against rogue ninjas together or exploring mysterious places in the Naruto world.
Naruto might be intrigued by Nunnaly's calm and gentle nature. He could introduce her to his friends in the Hidden Leaf Village. They could have conversations about their different worlds. For instance, Naruto could tell Nunnaly about his dreams of becoming Hokage, and Nunnaly could share her own hopes for a peaceful world.
The characters could interact through a magical portal. For example, Naruto might accidentally stumble through a portal into the Please Teacher world. He'd be confused at first but then start to make friends with the characters there, sharing his ninja stories.
The characters could interact in combat. For instance, Legolas' archery skills could be compared and contrasted with Naruto's ranged attacks using shurikens. They might train together and learn new techniques from each other.
Another way is to put her in different relationships. Let her interact with characters she didn't have much to do with in the original series. For example, if she were to meet some of the more radical anti - Britannian groups. Her reactions to their ideologies and methods could be used to show her growth and the evolution of her own beliefs. She could be conflicted between her loyalty to her family and her understanding of the oppressed people's cause.
They could interact through music. Since Miku is a virtual singer, her music might have an impact on Naruto. For example, her upbeat songs could give Naruto energy during a battle. Naruto, in turn, could teach Miku about the ninja way and how to be brave in the face of danger.
Well, Mario could teach Naruto about the power - ups in his world. Naruto, being curious, would be eager to try them out. For instance, when Naruto eats a Super Mushroom, he might gain increased strength and speed in a way similar to his Sage Mode but with a Mario - style twist.
In a 'naruto gotham fanfic', Catwoman could be intrigued by Naruto's agility and his different approach to getting around. She might playfully challenge him to a race across the rooftops of Gotham. Meanwhile, Naruto would be trying to understand the complex web of relationships between the heroes and villains in Gotham and would be constantly making missteps due to his lack of knowledge of the city's ways.
Conor might initially be in awe of Achilles. Since Achilles is a great warrior, Conor could look up to him and try to learn from his combat skills. For example, he could ask Achilles to teach him how to use a spear effectively.
Aladdin could be in awe of Hercules' strength. He might ask Hercules to show off his feats of strength, like lifting a huge boulder. Hercules, in turn, would be interested in Aladdin's street - smart ways. For example, Aladdin could teach Hercules how to haggle in the marketplace.
Naruto would probably be very friendly and open with the good characters. For example, he would likely be excited to meet Twilight Sparkle and would share his stories of his own world with her. He might be a bit cautious around Nightmare Moon at first, but once he realizes she's a threat, he would be very confrontational.
Another possibility is that a villain in the Naruto world tries to use Nunnaly for her unique knowledge or skills. The shinobi of the Hidden Leaf, including Naruto, would then have to protect her. In the process, Nunnaly could learn about the values of the shinobi world like loyalty and perseverance.