failed to load mods: atomic-arig/data-final-fixes.lua:180: attempt to index field 'unit' (a nil value)
stack traceback:
atomic-arig/data-fiinal-fixes.lua:180: in main chunk

this crash happens when the mod can't find a science pack amount on the Kovarex Enrichment Process tech, so I'm assuming you've changed the mod settings for Nuclear Science to make Kovarex a trigger tech. I'm uploading an update (1.0.3) so that the mod detects this now, so let me know if it fixes your issue.

I'm getting the same error on version 1.0.4, what do you think could be causing it:
Failed to load mods: atomic-arig/data-final-fixes.lua:123: attempt to index field 'vulcanus-arig' (a nil value)
stack traceback:
atomic-arig/data-final-fixes.lua:123: in main chunk

edit: this mod is incompatible the Redrawn Space Connections mod by thesixthroc

thanks for calling out the source for the incompatibility, I've just put in a small fix and it doesn't crash on my end now. Let me know if this works