Should the Nominations for Language of the Month post be converted to a community wiki? What are the pros and cons of doing so?
Community Wiki posts are specifically for posts that are edited often by multiple members of the community. The LOTM nominations body is a perfect example for this, and so the question should be made CW.
Unfortunately, making a question into a Community Wiki also makes all answers to that question Community Wiki as well, which appears to be the biggest objection to this. This is an unfortunate side effect of the Community Wiki tool, and an ideal resolution of this would to be to only CW the question, and leave the answers as is.
This, unfortunately, isn't an option, and, in my opinion, the downsides of making a nomination CW are negligible. Mostly, the nominations posts are about the languages, not about any single person, and we should be encouraging people to edit in resources/pros/cons/information about the nominations if they believe them to be lacking. The only real drawback I can see is that using first-person language may get confusing, but this can be mitigated in a number of ways - if it's even an issue in the first place.
Overall, yes, I believe making the thread CW is a good idea.