My rabbits are indoors and I use a cardboard box with an entry and exit hole cut in the sides, high enough to contain the digging contents, but low enough they can hop into it. And I line the bottom with several layers of newspaper then rip up and crumple some of it to get them started digging and ripping it up.
It does get peed in, but they aren't in there all the time so it doesn't get overly soiled too fast. And when it starts to get too soiled I can usually just pull out the crumpled newspaper and layers on the bottom, and throw it out and reline the box. Sometimes the box gets soiled and I just toss it out and make a new one. Not all rabbits will decide their digging box is also a litter box. Maybe you'll luck out and yours won't want to.