If the chain had slipped it would have at least bent a few valves, so if the engine is running quiet now then seems to be unlikely. If the oil warning light came on then maybe that's where the real issue lies. The smoke does sound like a ring has gone, possibly due to oil starvation.
To be honest this is why I'm in two minds whether to replace my chains or not. I know at 93k they need doing - but so far the car has cost me nothing beyond routine servicing. How much money do you spend on a ten year old car?