Is your feature request related to a problem? Please describe.
As of October 2022 Microsoft has added the option "Open in new tab" to navigation links.
Today this is not possible to configure with PNP Powershell.

Describe the solution you'd like
Add-PnPNavigationNode should have an extra property of type bool called something like "OpenInNewTab"
This should also be supported in Get-PnPSiteTemplate and Invoke-PnPSiteTemplate

Describe alternatives you've considered
As far as I know there is no alternative to this

Additional context
Relevant Microsoft 365 roadmap