You would need to iterate through values create an array and the use csv node.
e.g.
[{"id":"93a283f7.87a68","type":"inject","z":"8d22ae29.7df6d","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{ \"d\":{ \"ItemValue 1\":100, \"ItemValue 2\":200, \"ItemValue 3\":300, \"ItemValue 4\":400 },\"ts\":\"2020-11-09T13:01:31.624030\" }","payloadType":"json","x":130,"y":1620,"wires":[["31d285a6.f18fca"]]},{"id":"31d285a6.f18fca","type":"function","z":"8d22ae29.7df6d","name":"","func":"let key = Object.keys(msg.payload.d),\nvalue = Object.values(msg.payload.d),\ntimestamp = msg.payload.ts;\nmsg.payload = [];\n\nfor(let a=0; a <= value.length; a++){\n msg.payload[a] = [];\n msg.payload[a][0] = timestamp; \n msg.payload[a][1] = key[a];\n msg.payload[a][2] = value[a];\n}\nmsg.payload.unshift([\"Timestamp\",\"ItemValueNumber\",\"ItemValue\"]);\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":290,"y":1620,"wires":[["ef5dfb10.e5a408"]]},{"id":"ef5dfb10.e5a408","type":"csv","z":"8d22ae29.7df6d","name":"","sep":";","hdrin":"","hdrout":"all","multi":"one","ret":"\\n","temp":"","skip":"0","strings":true,"include_empty_strings":"","include_null_values":"","x":430,"y":1620,"wires":[["9d874d5b.b4324"]]},{"id":"9d874d5b.b4324","type":"debug","z":"8d22ae29.7df6d","name":"","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"msg","x":630,"y":1620,"wires":[]}]
