Nested CASE expressions

When APPROVALSTATUS='9' then 
        case
         when exists (select * from USERINFO where
          userinfo.NETWORKALIAS = trvexptable.MS_IT_FINALAPPROVER
            and userinfo.enable=0)
            then 'Inactive Approver'
            else
            then 
             CASE
                WHEN TRVEXPTABLE.MS_IT_RECEIPTSRECEIVED=0 AND TRVPARAMETERS.MS_IT_RECEIPTMETHODS=0 THEN 'RECEIPTS PENDING'
                WHEN TRVEXPTABLE.MS_IT_RECEIPTSRECEIVED=0 AND TRVPARAMETERS.MS_IT_RECEIPTMETHODS=1 THEN 'In review' 
                WHEN TRVEXPTABLE.MS_IT_RECEIPTSRECEIVED=1 AND TRVPARAMETERS.MS_IT_RECEIPTMETHODS=1 THEN 'In review' 
                WHEN TRVEXPTABLE.MS_IT_RECEIPTSRECEIVED=1 AND TRVPARAMETERS.MS_IT_RECEIPTMETHODS=0 THEN 'In review' 
                end     
            END
  END AS 'ApprovalStatus'

I am writing a case where all the outputs should be showed for inactive users receipts pending in review

the above syntax is wrong. Can anyone help with syntax? please