Technically we have a separate mod thats you relocate block models from the vanilla/forge json handler to the chisel json handler. You can find the proof-of-concept here. It's not stable and requires Chisel in 1.9.0 to run.
All you need to do is to go to the regular blockstate.json, and put ctm: in front of the model name. I.E. "ctm:minecraft:oak_log". For anything that happens after that, you can refer to the Chisel json assets until we make proper documentation.