I had an on-campus interview for a tenure track position last week in the US. The department chair told me that the results should be available within week. By today, a week is passed away. Is it ok to contact the department chair to ask her about the interview results and If I was selected to get a job offer or not?
I would wait for a few more days, actually. You don't want to seem too eager. If you are high on the list, you may still need to negotiate a few things, and it is better to be a bit calm about it. Let them come to you.
It is what it is, of course.
But if you have other decisions to make immediately, then you may need to ask now. Otherwise, patience is suggested.