The reason Chidori is a difficult boss is that she has no weaknesses. Instead, she absorbs fire and heals herself. While you won't need to deplete all of her HP to beat her, it can be difficult to ...

Fire Style: Fireball Jutsu ... Not a bad start at all, for number 10. Chidori, (which roughly translates to "One Thousand Birds") is one of the coolest jutsus to ever exist.