Board Thread:Show-Related Questions and Answers/@comment-27094327-20151019041819/@comment-27094327-20151022145053

Well, clearly anything Jafar did doesn't count. He explicitly got an exemption from the laws of magic.

As for Nyx only being in charge of her magical waters, I agree. However, I always saw a sort of implication that the waters were the source of magic overall. They were said to flow through all the magical lands; the well in Storybrooke was the mechanism by which magic came back; and, of course, it was through the power of the well (indirectly) that Jafar and Amara broke the laws of magic.