Change user nickname

C:\Users\Elève\Desktop\Project\HeartOfBot\Commands\testvalidation.js:147
                    message.guild.members.get(val[0].User).setNickname(`${val[0].King}`)
                                          ^

TypeError: message.guild.members.get is not a function
    at Query.<anonymous> (C:\Users\Elève\Desktop\Project\HeartOfBot\Commands\testvalidation.js:147:43)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)

Node.js v17.0.0