Why is there a Jynx on EM's bench? Also, for convenience's sake, could the benched Pokemon please include their statistics blocks?
Blizzard - Blizzard - Icy Wind
If successful p/e move, use Toxic Spikes on the first instance, and use Spikes on the second instance, pushing back in each case.
If damaging Steel-type attack and Chesnaught has more than 26 HP and your abilities include Protean, use Hidden Power that action and push back.
If damaging Fighting-type attack and you move before Chesnaught based on speed order and your abilities include Protean, use Extrasensory that action and push back.