jPCT is a 3D engine, it's not a game engine (albeit it has elements that go into that direction). So yes, you have to build such things yourself. At leasts you want these chunks to stream and load/unload on demand. If all you need is spatial subdivision, you could use jPCT's octree support.
If you do make your own solution, I suggest to do some tests first to see what you really need. I've seen cases where people were convinced that they needed some highly sofisticated chunk management when the best thing to do would have been to render the whole thing in one draw call.
Edit: For example...the terrain for my RPG is rendered as one large (more or less) model, because that's faster than splitting it into several draw calls by using an octree. The octree is used for collision detection though.