I have that problem with my puppy; I bet that some of the small dog chew toys would work such as:
Or if you can grow or obtain a catnip plant then you could use the stalks as chew toys, maybe there is another plant that would work similar.
I have also heard of spraying the cords with something unpleasant to taste like vinegar and cayenne pepper or something. I think mainly you need to find a distraction, something more interesting than the cords.
Make him toys that he will have to work to get treats out of. similar to the 'kongs' they have for dogs, but more cat-oriented and complex. If you made a big thing like this :
http://www.petco.com/product/103839/North-American-Pet-Classy-Kitty-Deluxe-Cat-Tree-With-Two-Story-Condo.aspx?CoreCat=CatSFC_CatFurniture -out of cardboard and scrap carpet,
and then, made some little holes in different areas with different treat holding contraptions. maybe you could change them up a bit so it doesn't become boring.