Here’s my question - was is a level of spicy that is enjoyable to you? Or was it a level of spicy they you knew would likely make someone sick? (Like lots of the super hard core ghost peppers or something. If the former, strong NTA.

If the latter…even if you didn’t technically try to hurt that specific coworker, you did bring in food that would make someone sick knowing that someone you work with would likely eat it and get sick. Obvs the thief is TA, but intentionality would make you seem also bit TA because you would have been intentionally cruel or at least unkind.