When you try to transliterate a word from a Non-English alphabet into an English one, it leaves a lot to the imagination. And you get variant spellings because the "real" spelling does not use English letters at all.

The matter is made worse in this case because the first letter of Chanukah is a "Chet."

It is a sound that many people who have no experience with either Hebrew or Arabic find hard or impossible to pronounce. They often mis-speak it as an "H" sound.

But I don't think how it's spelled really matters at all IMHO ! It's the holiday that matters, the festival of lights !