Actually, nope. No ideas here from me. Sorry bro, but I would really like to help but I would need a better understanding of the situation at hand here.
Something wrong with evaluation?

says 1-0 or 0-1 for me, looks fine. maybe clear cache, delete cookies, restart, etc. most basic solution you can attempt

A link to then game would help.
"NaN" stands for not a number and typically occurs when code tries to display a value that has not been set., i.e. a bug.
Whenever I finish a game where one side is mated; when I analyze it shows "NaN" as the eval. Got any ideas?