PL/SQL :: Referencing Element In Nested Collection

I have a table called dept table with nested collection as below. Nested Table Collection:

create or replace
type courselist as table of varchar2(64) Table Using Nested Table Collection: 
CREATE TABLE "FCSDWH_STG"."DEPT"
   ( "NAME" VARCHAR2(20 BYTE),
  "DIRECTOR" VARCHAR2(20 BYTE),
  "OFFICE" VARCHAR2(20 BYTE),
  "COURSES" "FCSDWH_STG"."COURSELIST"
   )  Content Of Table:NameDirectorofficecoursesAccountingJames CharlesUNOFCSDWH_STG.COURSELIST('natural science','chemistry','Computer Science','Computer Science') 

I am trying to select and print an element from nested table collection using below plsql block.

MY_COURSE VARCHAR2(64 CHAR);
BEGIN
SELECT courses INTO MY_COURSE FROM TABLE(SELECT COURSES FROM DEPT) where courses='chemistry';
DBMS_OUTPUT.PUT_LINE(MY_COURSE);
END; Error Message:
PL/SQL: ORA-00904: "COURSES": invalid identifier