According to the post, 8XO, Oh!GG, RV, Taemin, 127+DREAM, and SJ will be the confirmed performers. The concert is slated to be held at the Estadio Nacional in summer (winter here in the Northern Hemisphere; EN's capacity is said to be almost 38K). The final lineup and schedule will be finalized next month.
Source | Agenda Musical (twitter, web)
Chilean SM stans, are you ready? (Still bitter SM is consistently skipping this country in Asia with one of the biggest supporters of its artists, which is my country)