{{ $json.body.events[0].type }}

[
    {
    "text": "Hello",
    "replyToken": "d6a242a2b80f48fb9ac66adedf35f5d7"
    }
]

[
    {
        "chatInput": "Hi",
        "replyToken": "a3169e5ae5a1449aaea4e0aedc58afae"
    }
]

let requests
let message = {}
for (const item of $input.all()) {
  requests = item.json.body
}
if ('events' in requests) {
  if ('message' in requests['events'][0]) {
    if (requests['events'][0]['message']['type'] == 'text' &&
        'text' in requests['events'][0]['message']) {
      message = {
        'text': requests['events'][0]['message']['text'],
        'replyToken': requests['events'][0]['replyToken']
      }
    }
  }
}
return message

{
  "replyToken": "{{$node["Code"].json["replyToken"]}}",
  "messages": [
    {
      "type": "text",
      "text": "{{$node["Code"].json["text"]}}"
    }
  ]
}