I can't tell if this is just a general mixin-error or a mod compatibility with NostalgicTweaks. Please take some time to review the files below, thank you!

log:

latest.log

suggestive BetterLeveling crash-log:

crash-2023-02-07_13.57.21-fml.txt

p.s : your mod is titled 1.16.5 despite being advertised for 1.18. This is the version in question. link.

The mod you are using is for version 1.16.5, not 1.18.2.
I just saw that I had marked it as 1.18 version in Curseforge.
It is already fixed. Please use latest 1.18.2 here.