According to fivethirtyeight Russia is the biggest overperformer so far (9 medals above expectation), followed by Italy (7 medals above expectation) and Japan (5 medals above expectation). They predict that Norway will win the most medals (34), followed by Russia (28), Canada/USA (27), Germany (25), Netherlands/Austria (19), Sweden (18), Japan (17) and Italy (16). I think not many people would have predicted Italy to win more medals than Switzerland/China and at least as many medals as France.
https://projects.fivethirtyeight.com/winter-olympics-medal-count/