# Begin the process
$loadInfo1 = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
$loadInfo2 = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.Runtime")
$loadInfo3 = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.UserProfiles")

# Change to match your tenant information
$webUrl = "<your-site-url>"
$username = "<your-admin-login>"
$password = "<your-admin-password>"

$securePass = ConvertTo-SecureString $password -AsPlainText -Force

$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($webUrl)
$ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, $securePass)

# Get the collection of navigation nodes from the quick launch bar
$web = $ctx.Web
$quickLaunch = $web.Navigation.QuickLaunch

# Add a new navigation node
$navNode = New-Object Microsoft.SharePoint.Client.NavigationNodeCreationInformation
$navNode.AsLastNode = $true
$navNode.Title = "Site Contents"
$navNode.Url = $web.Url + "_layouts/15/viewlsts.aspx"
$navNode.IsExternal = $false

$ctx.Load($quickLaunchColl.Add($navNode))
$ctx.ExecuteQuery()

Write-Host "Done!"