Earlier I had issues getting the plugin to work, but I figured it out! We have 3.015, and we wanted to create a destroyed world, and it won't generate without turning the biomes into deserts, which we have IncludeDecayedNature: false. Is there any way to fix this?

Sorry I missed this request/bug. I will take a look at it soon

I looked into this issue @echurchill, this happens because if the world generator is set to Decayed, it will enforce a default true value for DecayedNature (it will overwrite the value in the config). The solution is to use the regular generator with no style set, and use the individual decayed options in the config to achieve the effect you're after