Short answer: you can’t.

Rabbits are going to chew. What you CAN do is provide lots of other fun chewable distractions like (non dyed) boxes & paper, apple sticks, wooden toys, etc. Give them a problem to solve (aka chew) nearby “problem” areas like this. My rabbit really likes to chew on the bedside table so I started putting Timothy hay cubes from small pet select in front of the table. Now when he goes to chew the table, he finds a timmy cube instead and enjoys that. Giving them fun distractions and solvable problems will help to cut down on instances like this. It isn’t guaranteed to 100% eliminate them, but it’s been a great help for us!