Board Thread:Boruto: Naruto the Movie/@comment-24992241-20160112202210/@comment-2005101-20160113020213

UltimaDude wrote: It was stated that Sasuke's nature affinity is lightning Don't recall any instance in the manga specifying which chakra nature Sasuke had an affinity for.

Before awakening the Rinnegan(which makes them all fair game), lightning was the safest bet due to the manner in which Sasuke relied on it. But that could have been due to Raiton's inherent utility compared to Katon.