Hmm... Weird. :/ I think that should work on Oldrim, so why not SSE? Maybe make sure that they're the exact same names and folder paths? I haven't used NMM in a long time though, so I don't know how I can help much. I personally use Mod Organizer, which makes making mods easier in my opinion, since you can easily enable and disable mods without uninstalling and re-installing, as well as keeping the data folder clean. Have you tried doing a new save? Maybe try using [Archive] bInvalidateOlderFiles =1 in your Skyrim ini, or running NMM as administrator? Also, does your mod have an .esp? Is it in a BSA format? I've heard that if a BSA doesn't have a matching .ESP, it won't load in Skyrim.