Nuclearcraft 1.20.1 Minecraft 1.20.1
Mods such as Mekanism, Create, Thermal, Extreme Reactors, Immersive Engineering, Industrial Foregoing are installed

ore_generation.txt

I have found that any mods that add dimensions break ore gen.
Ex (the Abyss II, RFTools Dimensions, Dimensional Dungeons, Ad Astra, Advanced Mining Dimension)

Ok. I was able to reproduce this on my dev env