I did look into this a few months ago, just after the Brazil service started. What I noticed was that LATAM's own system meant that PUQ-MPN would be unlikely to show up since LATAM's sliding scale system effectively parked it off into the "low but not the minimum" level of LATAM Points, thereby taking it off Avios. Same for GRU. I think I did find a single Córdoba flight on Avios (it was only a once a month service anyway). However I did find on Avios at least a few SCL-MPN services, thanks to LATAM's Married Segment issue just for once working in travellers' favour. I've had a look just now, and my feeling is that at the moment the LATAM end is down, which isn't unusual.

Going forward, anyone looking to do this is probably best to participate in LATAM Pass, at least in terms of getting a good discount on off peak services. LATAM is still indicating that it wants some sort of relationship with oneworld airlines, excluding AA, until at least September 2020. Clearly in the current conditions this is somewhat hypothetical.