Board Thread:Theories and Speculation/@comment-27717552-20160513151229/@comment-28575329-20160609230530

Saying they're related due to them both being hand-held is a tenuous link (would you say that Twin Lion Fists is related to the Rasengan?), and as jutsu they are almost opposites: Rasengan is a compressed sphere of rotating chakra, Chidori is a shapeless mass of wildly agitated chakra. It seems pretty clear that knowing one wouldn't help you learn another, considering how different they are. Whether Kakashi somehow got the idea for the Chidori from the Rasengan is irrelevant, because, well, he's a fictional character and doesn't exist outside of the story lol (and in the story, he gives no indication that this was the case). Purely for the sake of our own edification, we should acknowledge that the Chidori and Rasengan are two distinct, unrelated jutsu.