If you are looking for a solution which will fit the base game and both expansion into one box, check out my deluxe version on Cults.

Deluxe Treasure Chest for Tiny Epic Dungeons: https://cults3d.com/en/3d-model/game/tiny-epic-dungeons-deluxe-treasure-chest-storage-box

Deluxe Treasure Chest Preview: https://youtu.be/4ZDGOMQj118Insert for Tiny Epic Dungeons.

This insert fits everything from the base game as well as the Potions & Perils mini-expansion.

Does not work with sleeved cards. The insets for the minis are loose enough that it should not cause damage to the finish if you paint the minis, but should hold them in place so they don't rattle around in the box. If you order and orientate the minis as shown in the picture, there should be a very narrow gap between them and the token holder.

I hope you enjoy the design and I am open to any suggested edits.