Hope you like ordinary soft drinks, ordinary coffee and even more ordinary boxed chocolate biscuits for the flight SCL-PUQ-MPN.
Expect to do Chile Immigration (departure) at PUQ. If you do it at SCL it causes no end of confusion as the PUQ people think you have already left Chile earlier that day.
The flight is domestic as it departs SCL (since it goes via PUQ). Just hope your bags are not accidently offloaded at PUQ as they will stay there until you come back from MPN. If connecting from an earlier SCL-PUQ flight at PUQ, make absolutely sure you know how your bags are tagged (or they will be at the carousel at PUQ when you are flying to MPN).
If you coincide with a tour group going to MPN, expect to be bumped to an earlier flight SCL-PUQ.