It depends on the context. If it's a battle of pure physical strength and chakra, Naruto might have the edge as he has years of experience and has faced more powerful foes. But Boruto has some unique abilities like his Jougan. So if the fight involves using new - age ninja techniques, Boruto could surprise Naruto.
Maybe in the fanfiction, Jiraiya is summoned by a new jutsu gone wrong. When he meets Boruto, he mistakes him for Naruto at first. As they interact, Jiraiya realizes Boruto's own unique struggles. He shares his wisdom about handling the expectations that come with being a ninja from a famous family, and Boruto learns a great deal from him.
In this fanfiction, Boruto might learn some unique ninja techniques from Jiraiya. Jiraiya could see the potential in Boruto and train him in his own unorthodox ways. Maybe Boruto would be introduced to Jiraiya's toad summoning, which could add a whole new dimension to his combat abilities.
Maybe a fanfic where Naruto and Boruto are pitted against each other in a virtual reality battle. It could be part of a training exercise that gets out of control, and they start using their real skills and emotions, leading to a intense and revealing fight.
In a fanfic, it really depends on how the author writes it. But if we base it on the original series' power scaling, Naruto has a higher chance of victory. He has learned from many battles and has a wider range of abilities compared to Jiraiya. Also, Naruto has a strong will that could give him an advantage when facing his old master in the Edo Tensei form.
Well, a possible plot point might be that Edo Jiraiya still retains some of his old teachings and uses them in an unexpected way against Naruto. For example, he could use some forgotten jutsu that Naruto has to figure out how to counter. This would add an element of mystery and a test of Naruto's knowledge and growth.
Perhaps an old enemy of Jiraiya who was thought to be defeated but has now resurfaced. This antagonist targets Boruto to get to Jiraiya, thinking that by harming Boruto, he can draw Jiraiya out and finally get his revenge. He would be a powerful and cunning foe, making it difficult for Jiraiya and Boruto to face him.
Jiraiya could act as a mentor to Boruto. He might correct Boruto's mistakes in combat or give him advice on how to handle difficult situations. Boruto would listen intently, trying to soak up all the knowledge from this legendary ninja. And they could also have some light - hearted moments, like joking about Naruto's clumsy moments when he was young.