Where is the one chewing? One of my rabbits will leave carpeting alone if they’re free to roam, but the second there’s something in their way, it’s dig dig dig, scratch scratch CHEWCHEWCHEW. Trying to get whatever’s behind it or under it. It’s a challenge, and they must meet it. The other doesn’t usually go after carpet – but if there’s anything poking up (a rug that’s bent somewhere, or that has tassels) suddenly MUST be attacked and chewed on. If there’s a particular spot your bun likes, perhaps get a scrap piece of carpet to lay OVER the area they like to chew up. You can even use double-sided tape to keep it in place?
I’m not sure why they’ve suddenly got the idea to destroy the fuzz, but I’ve learned it’s hard to actually argue with rabbits. Instead, I try to keep whatever they’re going after out of reach however I can. If they go after cords? Cord covers. If they go after baseboards? plastic coverings or wire set out about an inch from the wood. Furniture? Plastic casing again.
I figure if they’re going to chew up carpet, a 1′ x 2′ piece of sample carpet taped down should keep them from destroying, if they like a particular spot. Otherwise, it looks like you might want to try linoleum over the carpet in the rooms they go in?