"Why do you look so nervous?"
Yes. Loosely I think the given translation is fine, given the differences between the languages, but I also think it's possible that the non-English native speaker who wrote this question mistook this "so" for an intensifier, rather than a demonstrative.
My own sense is that it would be equally, if not more, idiomatic here to use "那么" as compared to "很".
(Not to mention that this course doesn't currently follow any rules as to when "很" is required to be translated into something and when it's required to be left out entirely from the English.)