Board Thread:Theories and Speculation/@comment-1512913-20161119171442/@comment-1512913-20161207173706

Exactly, combined natures aren't basic natures combined, rather applied simultaneously. If you just combined Water chakra with Wind chakra, the result would be the Naruto-Yamato combo technique. Rather to get Ice, you apply change of nature to chakra of Water and change of nature to the same chakra of Wind as well, both at the same time, meaning the chakra gets changed to 2 different things at the same time rather than combined.