Last year I was flying with Iberia, stopover in Madrid. I booked well in advance, and paid around CHFr 250.- return. Iberia is also offering flights with stopover in Barcelona.
Air Berlin are offering flights to Zurich from Santiago via Palma de Mallorca, and they are cheap!
I heard about a direct bus from Santiago to Zurich, but don't know about timetables etc. And it takes ages to do the trip by bus...
Rolf