Lol, people, its already canon that Rasengan=Chidori. If Sasuke used Enton on his Chidori and Naruto matched it with Rasengan either:
1. Sasuke's Chidori was weakened due to lack of chakra, and using Enton merely put it back on its normal level (Highly doubt this is true)
2. Naruto's Rasengan was enhanced.
3. Enton didn't provide a boost in power (Doubt it)
Naruto obtained Kurama's chakra straight from him, thus his jutsu used Kurama's chakra, thus it was enhanced. Preta Path absorbs the chakra, and then disperses it throughout the body, that's probably why it wasn't enhanced. Nagato absorbed all of Killer B's V2 Chakra Cloak, were all of his moves buffed by Hachibi's chakra? No. They weren't.