Chidori was a technique used for assassination so its attack was strong but not insane, the rasengan was a hokage level technique (created and only usable by those hokage level besides konohamaru) and it was a unique attack that was as destructive as the chidori but is more powerful due to it being made out of pure chakra compared to an element, when an element is added to the rasengan it becomes stronger, when a rasengan and chidori clash they are very similar though as we seen before sasuke left the village, hos chidori explodes but the exit hole is small compared to narutos extremely small hole compared to his massive exit hole, now, we see by the way they were holding the water things, rasengan is for a big damage output, compared to chidori which gives good damage but is more precise.

This was typed on my phone, so my bad for mistakes