Does [ghov] mean "recognize" as in "to identify as something or someone previously seen, known, etc.," "to acknowledge," or both?
It means the former. It has never been used to mean the latter.
Thanks for the clarification!
Other sentences in this lesson accept "[subject] does" for a repeated verb, but this one marked me wrong for "nobody does". Am I missing some subtlety there?
No, if other sentences allow it, this one should as well. You are not missing a subtle difference.
"Did anybody recognize you? No. Nobody does." is an accepted translation (and has been for at least 8 months when the translations on this sentence were last edited). Is it possible that there was a different error that caused the rejection?