USA bank issued ATM card (with chip) for use in Korea

Your ATM or debit card that you use in the U.S. should work just fine in Korea, or most anywhere in the world for that matter. If you do not have one in the U.S., I would talk to whomever you bank with and make sure the ATM/debit card they issue would work there. Usually a major bank like Bank of America, U.S. Bank, Key Bank, etc., would be no problem. Credit Unions also issue cards that will work overseas, sometimes with lower rates than the major banks.

Schwab Bank.

You don't need a chip. Why bother ?