People forget that Naruto had not only the tailed beast Chakra reserves to dip into upon hitting zero, but also the uzamaki being known for their sealing and very high Chakra amount. Bro was blessed to be full of Chakra the moment he was born.
Most people forget that Hiruzen's sacrifice is the reason Orochimaru didn't take Sasuke's body. His arms were in such pain he had to change to a weaker body before Sasuke could even get there.
