You could get a ceramic tile to put down over the spot they like to chew. They might dig on it or lay on it. They might actually like it. Or you could get a cardboard box and put it over the spot.
Clapping your hands or saying NO in a loud firm voice might help too. But sometimes when you make a big deal about an item, it makes them want it more.
If they want a pillow to lay on, maybe you could get them a small pet bed. They might enjoy being able to lay and dig in that. And they're machine washable! Sometimes you can find them on sale at like Dollar General or I just saw some at TJ Maxx.
When I have to block my rabbit from things, I just put cardboard in front of it. My rabbit loves cords, so one cord (the stove) has a box and the trash can in front of so she can't get to it. And my NEW fridge has a huge bin of chicken feed and a grate thing in front of it, so she can't get to that one. She killed one fridge and will not kill the new one! The washing machine is also blocked off with a piece of granite and her food tin.
I agree though, you might want to find something else to attach the cord to the wall with. The duct tape will get weird. I think Command(3M) makes cord holders, for like Christmas time. They attach to the wall in a nice way and don't leave marks behind. I haven't ever used any of those products, so I can't say for sure that they don't leave marks. My guess would be that its better than tape.