attack on titan or boruto ?
Rasengan doesnt need the type of movement the Chidori needs. It's a more advance jutsu cause you need to do a ton of shit with Chakra but if you know how to do it is safer than the Chidori cause with the Chidori you need to run really fast towards the oponent while the Rasengan is more like an energy ball in your hand which means that if you have good Chakra control and tons of it you can do it from anywhere. Naruto on the other hand as a kid used clones as distraction in order to get close (because he couldnt do the Rasengan without the use of clones) to an enemy but as he grew older he was able to do a Ransengan from anywhere. Theres a Reason more people after Naruto have learned the Rasengan over the Chidori after all.
he's right you know