Navigation Settings csom Powershell for SharePoint online

You need to include the SharePoint.Client.Publishing.Navigation

You can change the values of the navigation source as per your requirement.

See below screenshot:

Try the below code in powershell:

#Credentials to connect to office 365 site collection url 
$url ="https://tenant.sharepoint.com/sites/home"
$username="[email protected]"
$password="yourpassword"
$Password = $password |ConvertTo-SecureString -AsPlainText -force

Write-Host "Load CSOM libraries" -foregroundcolor black -backgroundcolor yellow
Set-Location $PSScriptRoot
Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.dll")
Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.Runtime.dll")
Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.Taxonomy.dll")
Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.Publishing.dll")

Write-Host "CSOM libraries loaded successfully" -foregroundcolor black -backgroundcolor Green 

Write-Host "authenticate to SharePoint Online Tenant site $url and get ClientContext object" -foregroundcolor black -backgroundcolor yellow  
$Context = New-Object Microsoft.SharePoint.Client.ClientContext($url) 
$credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, $password) 
$Context.Credentials = $credentials 
$context.RequestTimeOut = 5000 * 60 * 10;
$web = $context.Web
$site = $context.Site 
$context.Load($web)
$context.Load($site)
try
{
  $context.ExecuteQuery()
  Write-Host "authenticateed to SharePoint Online Tenant site $url and get ClientContext object succeefully" -foregroundcolor black -backgroundcolor Green
}
catch
{
  Write-Host "Not able to authenticateed to SharePoint Online $_.Exception.Message" -foregroundcolor black -backgroundcolor Red
  return
}

#set both current and global navigation settings to structural
Write-Host "set both current and global navigation settings to structural started" -foregroundcolor black -backgroundcolor yellow
$taxonomySession = [Microsoft.SharePoint.Client.Taxonomy.TaxonomySession]::GetTaxonomySession($context)
$navigationSettings = New-Object Microsoft.SharePoint.Client.Publishing.Navigation.WebNavigationSettings $context, $context.Web

#set both current and global navigation settings to structural
$navigationSettings.CurrentNavigation.Source = "portalProvider"
$navigationSettings.GlobalNavigation.Source = "portalProvider"

#For Display the same navigation items as the parent site
#$navigationSettings.CurrentNavigation.Source = "inheritFromParentWeb"
#$navigationSettings.GlobalNavigation.Source = "inheritFromParentWeb"

#For Managed Navigation
#$navigationSettings.CurrentNavigation.Source = "taxonomyProvider"
#$navigationSettings.GlobalNavigation.Source = "taxonomyProvider"

$navigationSettings.Update($taxonomySession)

try
{
$Context.ExecuteQuery()
Write-Host "setting both current and global navigation settings to structural Completed" -foregroundcolor black -backgroundcolor green
}
catch
{
Write-Host "Error while setting both current and global navigation settings to structural" $_.Exception.Message -foregroundcolor black -backgroundcolor Red
}


// disable quick launch navigation including subsites and pages    
$context.Load($web.AllProperties)
$Context.ExecuteQuery()
$web.AllProperties["__IncludeSubSitesInNavigation"] = "False"
$web.Update()
$Context.ExecuteQuery()

$web.AllProperties["__IncludePagesInNavigation"] = "False"
$web.Update()
$Context.ExecuteQuery()

#set dynamic child limit for current navigation
$web.AllProperties["__CurrentDynamicChildLimit"] = 20
$web.Update()
$Context.ExecuteQuery()

#set dynamic child limit for global navigation
#$web.AllProperties["__GlobalDynamicChildLimit"] = 20
#$web.Update()
#$Context.ExecuteQuery()