1. Nuclearcraft Neoteric - 1.2.0, Forge - 47.4.0
2. 
   latest.log

This log gives me no information what happened.
Also i was not able to reproduce the issue.

Sorry about that, im also realizing I didnt give much of an explanation. When pressing create new world, that is the message that pops up. I disabled Not Enough Crashes to try and allow a full crash or something similar, but it seems that the issue is having NuclearCraft and Not Enough Crashes in this modpack I am playing.

edit:
Nevermind, it kind of just works now, if you would like im pretty sure I can give a changelog of what mods were removed from then. Updated mods may be a little more difficult.