How to write Case statement or IF ELSE (possibly) statement within IFNULL

Question

I am trying to use Case statement or IF ELSE statement within IFNULL function to specify in more details of options.

If I uncomment the IF statement where it starts with IF(t.Type_id IN (7777 , 9999), it would not cause error, but when I try to use CASE statement, it gives that error ("Select" is not valid at this position for this server version, expecting '(', with).

I am trying to use CASE statement to be more specific, but if there is any way to use IF ELSE statement to specify t.Type_idin (4444, 2222) then 'VIDEOVISITS - RETURN' and not causing this error, please let me know. Thanks in advance.

SELECT       
    IFNULL(IF(`t`.`NRP_classification` NOT IN (
                    'NEW',
                    'TELEPHONE'),
                'OTHER NC',
                IF(
                    `t`.`NRP_classification` = 'VIDEOVISITS',
                    //Trying to replace from here: 
                    IF(`t`.`Type_id` IN (7777 , 9999),
                        'VIDEOVISITS - NEW',
                        'VIDEOVISITS - RETURN'
                       ),
                    `t`.`NRP_classification`
                    //Trying to replace until here   
                    /*
                    case `t`.`NRP_classification` = 'VIDEOVISITS'
                        when `t`.`Type_id` IN (7777 , 9999) then 'VIDEOVISITS - NEW'
                        when `t`.`Type_id` IN (4444, 2222) then 'VIDEOVISITS - RETURN'
                    end as `t`.`NRP_classification` 
                    */
                   )                     

            ),
            'OTHER NC') AS `Type`
       FROM
    ((((((((((((((SELECT 
        `DONI_db`.`appointment`.`Appt_id` AS `Appt_id`,
            `DONI_db`.`appointment`.`CSN` AS `CSN`,
            `DONI_db`.`appointment`.`N` AS `N`,
            `DONI_db`.`appointment`.`Date` AS `Date`,
            `DONI_db`.`appointment`.`Time` AS `Time`,
            `DONI_db`.`appointment`.`Len` AS `Len`,
            `DONI_db`.`appointment`.`Status` AS `Status`,
            `DONI_db`.`appointment`.`Type` AS `Type`,
            `DONI_db`.`appointment`.`LOS` AS `LOS`,
            `DONI_db`.`appointment`.`Made_date` AS `Made_date`,
            `DONI_db`.`appointment`.`Rescheduled` AS `Rescheduled`,
            `DONI_db`.`appointment`.`SD_canceled` AS `SD_canceled`,
            `DONI_db`.`appointment`.`Canc_date` AS `Canc_date`,
            `DONI_db`.`appointment`.`Canc_reason` AS `Canc_reason`,
            `DONI_db`.`appointment`.`CI_startTime` AS `CI_startTime`,
            `DONI_db`.`appointment`.`CI_endTime` AS `CI_endTime`,
            `DONI_db`.`appointment`.`VS_startTime` AS `VS_startTime`,
            `DONI_db`.`appointment`.`AVS_time` AS `AVS_time`,
            `DONI_db`.`appointment`.`Encounter_status` AS `Encounter_status`,
            `DONI_db`.`appointment`.`EncClosure_provID` AS `EncClosure_provID`,
            `DONI_db`.`appointment`.`Cosign_provID` AS `Cosign_provID`,
            `DONI_db`.`appointment`.`PrimaryDx_ICD10` AS `PrimaryDx_ICD10`
    FROM
        `DONI_db`.`appointment`
    WHERE
        `DONI_db`.`appointment`.`Type` NOT IN ('2100' , '4493', '5044', '5045', '5183', '5225')
            AND `DONI_db`.`appointment`.`Date` >= '2016-07-01')) `appt`
    JOIN `DONI_db`.`type` `t`)
    JOIN `DONI_db`.`appt_status` `as`)
    LEFT JOIN `DONI_db`.`user` `ulos` ON (`appt`.`LOS_authProviderID` = `ulos`.`User_id`))
    JOIN (SELECT 
        `DONI_db`.`appt_pds`.`APDS_apptID` AS `APDS_apptID`,
            `DONI_db`.`appt_pds`.`APDS_provID` AS `APDS_provID`,
            `DONI_db`.`appt_pds`.`APDS_deptID` AS `APDS_deptID`,
            `DONI_db`.`appt_pds`.`APDS_specID` AS `APDS_specID`,
            `DONI_db`.`appt_pds`.`APDS_posID` AS `APDS_posID`
    FROM
        `DONI_db`.`appt_pds`
    WHERE
        `DONI_db`.`appt_pds`.`APDS_type` = 'New') `apds_np`)
    JOIN `DONI_db`.`department` `d`)
    JOIN `DONI_db`.`specialty` `s`)
    JOIN `DONI_db`.`user` `unp`)
    LEFT JOIN (SELECT 
        `apds_op`.`APDS_apptID` AS `APDS_apptID`,
            `apds_op`.`APDS_provID` AS `APDS_provID`,
            `apds_op`.`APDS_newProv` AS `APDS_newProv`,
            `uop`.`Lastname` AS `LastName`,
            `uop`.`Name` AS `Name`
    FROM
        (((SELECT 
        `DONI_db`.`appt_pds`.`APDS_apptID` AS `APDS_apptID`,
            `DONI_db`.`appt_pds`.`APDS_provID` AS `APDS_provID`,
            `DONI_db`.`appt_pds`.`APDS_posID` AS `APDS_posID`,
            `DONI_db`.`appt_pds`.`APDS_newProv` AS `APDS_newProv`
    FROM
        `DONI_db`.`appt_pds`
    WHERE
        `DONI_db`.`appt_pds`.`APDS_type` = 'Old')) `apds_op`
    LEFT JOIN `DONI_db`.`user` `uop` ON (`apds_op`.`APDS_provID` = `uop`.`User_id`))
    WHERE
        `uop`.`Type` = 'R'
            OR `uop`.`User_id` = 12
    GROUP BY `apds_op`.`APDS_newProv` , `apds_op`.`APDS_apptID`
    HAVING MAX(`apds_op`.`APDS_posID`)) `apds_op` ON (`apds_np`.`APDS_apptID` = `apds_op`.`APDS_apptID`
        AND `apds_np`.`APDS_posID` = `apds_op`.`APDS_newProv`))
    LEFT JOIN `DONI_db`.`clinic_dpp` `cdpp` ON ((`cdpp`.`CDPP_provID` IS NULL
        OR IF(`apds_op`.`APDS_provID` IS NULL, `apds_np`.`APDS_provID`, `apds_op`.`APDS_provID`) = `cdpp`.`CDPP_provID`)
        AND `d`.`Department_id` = `cdpp`.`CDPP_deptID`))
    LEFT JOIN `DONI_db`.`clinic` `c` ON (`cdpp`.`CDPP_clinicID` = `c`.`Clinic_id`))
    LEFT JOIN `DONI_db`.`program` `p` ON (`cdpp`.`CDPP_progID` = `p`.`Program_id`))
    JOIN `DONI_db`.`enc_status` `es`)
WHERE
    `appt`.`Type` = `t`.`Type_id`
        AND `appt`.`Status` = `as`.`ApptStatus_id`
        AND `appt`.`Appt_id` = `apds_np`.`APDS_apptID`
        AND `apds_np`.`APDS_deptID` = `d`.`Department_id`
        AND `apds_np`.`APDS_specID` = `s`.`Specialty_id`
        AND `apds_np`.`APDS_provID` = `unp`.`User_id`
        AND `appt`.`Encounter_status` = `es`.`ES_id`
        AND `d`.`toExclude` = 0