Islamabad is 8 hours ahead of Santiago
Best overlap: 8:00 AM to 10:00 AM in Santiago is 4:00 PM to 6:00 PM in Islamabad.
Santiago and Islamabad overlap from 8:00 AM to 10:00 AM (Santiago) to the equivalent 4:00 PM to 6:00 PM in Islamabad — that's your meeting window. The shared window is only 2 hours — treat 8:00 AM in Santiago (4:00 PM in Islamabad) as the one fixed point and plan everything else around it. A quick caveat — Santiago's clocks move for daylight saving and Islamabad's don't, so the times here are right for only part of the year.