Testing out in the new Enigmatica 2 pack, and the chisel only gains XP by killing mobs. It doesn't seem like a config issue, as there is no config option to change something like this. Having it gain XP through the GUI or in-world would be best.

By Chisel do you mean the Tinkers Complement Chisel? If so, this might be an issue on that side based on how the compat is set up. Mind crossposting it on the Tinkers Complement tracker?

Oh, didn't realize it wasn't a vanilla Tinker's tool. I'll go ahead and post it there as well!

Edit: Here is the new thread in Tinkers Complement.