generate xml using oracle

You can use subselects in order to get the data for both the profile and the averageannualreturns nodes. For example:

select xmlelement("Component",
         xmlattributes('600564' as ID,
                       '1' as asmid,
                       'FactSheet' as def,
                       'Document' as type
         ),
        (
         SELECT XMLELEMENT("Profile",
                  XMLFOREST(
                    'example_port' AS "Port_ID",  
                    '30/11/2016' as "Inception_Date" 
                  )
                )
         FROM dual
        )                                 
) from dual;

I believe this is the sort of thing you would need (although I don't have your tables to test with):

select xmlelement("Component",
         xmlattributes('600564' as ID,
                       '1' as asmid,
                       'FactSheet' as def,
                       'Document' as type
         ),
        (
         SELECT XMLELEMENT("Profile",
                  XMLFOREST(
                    PCR.PORT_ID AS "Port_ID",  
                    to_char(p.port_start_dt, 'dd Mon yyyy') as "Inception_Date" 
                  )
                )
         FROM edp_admin.PORT_CLASS_REPORT PCR 
         JOIN edp_admin.PORTFOLIO p on (PCR.PORT_ID = P.PORT_ID and PCR.CLASS_ID = P.BASE_CLASS_ID) 
         where PCR.PORT_ID = 182 AND PCR.REPORT_ID = 472
        ),
        (
          SELECT XMLELEMENT("AverageAnnualReturns",
                   XMLELEMENT("TableData",
                     XMLAGG(
                       XMLELEMENT("Item",
                         XMLFOREST(
                           MPR.CLASS_ID AS "ClassID",
                           MPR.CLASS_NAME AS "ClassName",
                           NVL (NC.SUPERSCRIPT_TEXT,' ') AS "SuperScript",
                           NULL AS "SuperScript_TCE"
                         )
                       )
                     )
                   ),
                   XMLFOREST(
                     'Yes' AS "SupressLifeColumn",
                     'No' AS "SupressBenchColumn10yr",
                     'No' AS "SupressBenchColumn5yr",
                     'No' AS "SupressBenchColumn3yr",
                     'No' AS "SupressBenchColumn1yr"
                   )
                 )
          FROM EDP_ADMIN.SYSTEM_VALUE PCR 
          LEFT JOIN EDP_ADMIN.MPR_MIL_VIEW MPR ON (PCR.VALUE_NUM1 = MPR.PORT_ID AND PCR.VALUE_NUM2 = MPR.CLASS_ID AND MPR.CLASSIF_ID = 206) 
          LEFT JOIN EDP_ADMIN.PORT_CLASS_YIELD PCY ON (PCR.VALUE_NUM1 = PCY.PORT_ID AND PCR.VALUE_NUM2 = PCY.CLASS_ID AND MPR.PROFILE_DATE = PCY.PORT_CLASS_YIELD_DT AND PCY.YIELD_ID = 6) 
          LEFT JOIN EDP_ADMIN.PORTFOLIO_CLASS PC ON (PCR.VALUE_NUM1 = PC.PORT_ID AND PCR.VALUE_NUM2 = PC.CLASS_ID) 
          LEFT JOIN EDP_ADMIN.PORT_CLASS_MKT_PRICE PCMP ON (PCR.VALUE_NUM1 = PCMP.PORT_ID AND PCR.VALUE_NUM2 = PCMP.CLASS_ID AND PCMP.MKT_PRICE_ID = 12 AND MPR.PROFILE_DATE = PCMP.PORT_CLA_MKT_PRICE_PER_END_DT) 
          LEFT JOIN (SELECT DISTINCT R1.PORT_ID, R1.CLASS_ID, R1.PORT_CLASS_EXP_RAT_VALUE, R1.PORT_CLASS_EXP_RAT_DT FROM edp_admin.Port_Class_Expense_Ratio R1 INNER JOIN (SELECT DISTINCT PORT_ID, CLASS_ID, MAX(PORT_CLASS_EXP_RAT_DT) as MONTH_END_DATE FROM EDP_ADMIN.PORT_CLASS_EXPENSE_RATIO GROUP BY PORT_ID, CLASS_ID ) R2 ON (R1.PORT_ID = R2.PORT_ID AND R1.CLASS_ID = R2.CLASS_ID AND R1.PORT_CLASS_EXP_RAT_DT = R2.MONTH_END_DATE) ) PCER ON PCR.VALUE_NUM1 = PCER.PORT_ID and PCR.VALUE_NUM2 = PCER.CLASS_ID 
          LEFT JOIN EDP_ADMIN.FN_MIL_FS_CONCAT_NOTES_VIEW NC ON NC.PORT_ID = PCR.VALUE_NUM1 AND NC.CLASS_ID = PCR.VALUE_NUM2 AND NC.HYPO_TYPE = PCR.VALUE_CHAR1 
          WHERE PCR.CODE = 'MIL_FS_PERF_CONFIG' AND PCR.VALUE_NUM1 IN (182) AND PCR.VALUE_CHAR1 = 'UK' ORDER BY RANK   
        )                                   
) from dual;

Solution using appendChildXML and plsql:

DECLARE
  lComponentXML xmltype;
  lProfileXML   xmltype;
BEGIN
  --generate the component xml
  select xmlelement("Component",
           xmlattributes('600564' as ID,
                         '1' as asmid,
                         'FactSheet' as def,
                         'Document' as type
           )
         )
  INTO lComponentXML
  FROM dual;

  --generate the profile xml
  SELECT XMLELEMENT("Profile",
           XMLFOREST(
             PCR.PORT_ID AS "Port_ID",  
             to_char(p.port_start_dt, 'dd Mon yyyy') as "Inception_Date"
           )
         )
  INTO lProfileXML
  FROM edp_admin.PORT_CLASS_REPORT PCR 
  JOIN edp_admin.PORTFOLIO p on (PCR.PORT_ID = P.PORT_ID and PCR.CLASS_ID = P.BASE_CLASS_ID) 
  where PCR.PORT_ID = 182 AND PCR.REPORT_ID = 472;

  --append the profile xml to the component
  lComponentXML := lComponentXML.appendChildXML('//Component',lProfileXML);
END;