Reference them by attribute name:
create or replace type obj as object (
x int, y int
);
/
create or replace type obj_arr as table of obj;
/
declare
v obj_arr;
begin
v := obj_arr ( obj ( 1, 2 ), obj ( 3, 4 ) );
for rws in (
select t.x, t.y from table ( v ) t
) loop
dbms_output.put_line ( rws.x || ' ' || rws.y );
end loop;
end;
/
1 2
3 4