Has anyone tried this with chard?

Only other adjustment I make with chard specifically is to dial back on the salt with it b/c it has a noticeably higher sodium content than other greens. I learned this the hard way when I once added my usual amount of salt to my blanching liquid with chard and it turned out inedibly salty.

I've done something very similar with all sorts of greens, so I don't see why you couldn't do that with this recipe. In most cases, you can substitute one sort of leafy green for another pretty easily. Except for collard greens, which take longer to cook tender, most of them have the same short cooking times.