My chin seems to start tearing up his stuff (like the shedders he ignores or throwing hay and pellets everywhere) if he doesn't get a variety of chews. The same ones are boring. I'm glad I have access to a lot of wood types. I make him grape, apple, pear, and blackberry sticks. Plus he's got plenty of loofah (koolaid-dyed, which was fun and sorta like doing easter eggs-but leave out the sugar! and make sure it's not bleached or treated loofah). Besides chews, time out of the cage every day and his wheel are typically enough for Yuki. I project that he's bored more than he actually is, I would be sitting in a cage just chewing. So I've been working on plans for play structures for out of the cage, but I haven't been able to build yet.
If he's got a smaller cage, more playtime would help, and if you dont have a chin-spin or other wheel, I suggest saving up for one.
Also, they naturally are foragers, so some days I take whatever Yuki's treat was going to be-an organic Cheerio or rose hip or a bit of Post shedded wheat- and break it up even smaller and hide the pieces all around. I'm sure Yuki would rather gobble the treat down outright, but I'm sure he likes the game too.
If you have a staircase that's chin-proof-able and easy to block off on both ends, maybe that would be a nice change from a normal play area, Plus it's cute watching them hop up and down.
I think I'm out of ideas for now. I'll try to think of anything else Im missing.