FunctionsPublic/New-GraphTeamChannel.ps1

function New-GraphTeamChannel
{
    param([psobject]$accessToken, [string]$groupID, [string]$channelName)
    #
    # Create new unified group
    #
    $sendBody = @{
        "displayName" = "$($channelName)";
        "description" = "$($channelName)"
        } | ConvertTo-Json 
    
    $responseBody = Invoke-RestMethod `
        -Uri "https://graph.microsoft.com/v1.0/teams/$($groupID)/channels" `
        -Headers @{"Authorization" = "Bearer $($accessToken.AccessTokenCredential.GetNetworkCredential().password)"} `
        -Body $sendBody `
        -ContentType "application/json" `
        -Method POST

    $jsonResponse = $responseBody | ConvertTo-JSON

    $createdTeamChannel = ConvertFrom-Json -InputObject $jsonResponse

    return $createdTeamChannel
}