Brussels is 5 hours ahead of Santiago
Best overlap: 8:00 AM to 1:00 PM in Santiago is 1:00 PM to 6:00 PM in Brussels.
Shoot for 8:00 AM to 1:00 PM in Santiago; your Brussels colleagues will see that as 1:00 PM to 6:00 PM. Brussels is 5 hours ahead of Santiago, so the practical overlap is about 5 hours — generous enough for meetings, tight enough to be worth booking ahead.