Self plagarism with co-authors
The essence of plagiarism, self or otherwise, is an intention to mislead by passing something off as your original work when it is not. You can never be guilty of self-plagiarism if you say/write something along the lines "As I [and my colleagues] showed/claimed in ...".  If you repeat as an original comment something that is not original, it is irrelevant that you wrote its true original form with the collaboration of others.

That said, I am beginning to question the premise of this question. What kind of 'job talk' is that demands wholly new material never before published? That means material never before subjected to peer review - surely of lesser quality than peer-reviewed published stuff? And, anyhow, it is surely a practical impossibility to cite full references in a talk: your audience would either sleep or find something of more interest on their phones.