Add a Link to SharePoint Top Navigation Menu or Quick Launch using PowerShell

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#Variables for processing
$WebURL="http://sharepoint.crescent.com/teams/marketing"
$NavigationTitle="Employee Profile"
$NavigationLink="https://peoplesoft.crescent.com/employee/profile.aspx"

#Get the Web
$Web= Get-SPWeb $WebURL

#Get Top Navigation
$TopNavigation = $Web.Navigation.TopNavigationBar
#For Quick Launch, Use: Navigation.QuickLaunch

#Create a New Top Navigation Node
$node = New-Object Microsoft.SharePoint.Navigation.SPNavigationNode($NavigationTitle, $NavigationLink, $true)

#Add the Node
$TopNavigation.AddAsLast($node)

#Set the Target Property - Will work only when Publishing features is enabled
$node.Properties["Target"] = "_blank"

$node.Update