Thanks for contributing to Parf Edhellen!
I like this word, though it would probably be a good idea to record nirna “forced” separately. Also, depending on how old you want the word to be, it might come out as √NIDnā > ninda and I’m still pondering whether √NID or thakta- would be the preferable source ‘non-physical force’. For ‘voluntarily’ specifically I’d also like to throw nirmenen/nirmello “of/with will” based on Tolkien’s lintiénen “quickly, with speed”. I’ll ask for some other opinions.
Regarding the technical side of things, you should change the Group from “Eldamo — fan inventions” to “Neologism” since your formation doesn’t appear on Eldamo and I would encourage you to at least add links to the words mentioned, which you can do with the shorthand [[q:ú-]], [[q|nir-]].
gilruin · Gilruin
Depending on the age of the formation, úninda might be possible as well, restoring the d of its primitive Elvish root √NID, which became r between vowels in Quenya, but survives in the combination -nd-. This is illustarted by the past tense forms of nir-: archaic †ninden was eventually reformed to nirnen.