Adguard with NordVPN

Is it possible to use Adguard and NordVPN simultaneously ?
What is safer: Adguard DNS or NordVPN DNS ?
And can you use, for example, Adguard through NordVPN DNS ?

yes, supported to enable AdGuard Home and run the VPN client with NordVPN at the same time in the router.

I think both safe, but it depends on which one you trust more, or which one respond faster in your location.

After enabling the AdGuard Home, and you can fill in NordVPN DNS in its setting page.

How to configure a DNS server in Adguard Home to go through a VPN ?
I would like the DNS servers to come from the VPN provider, rather than from the DNS servers configured in AdGuard Home.
GL-MT6000; 4.8.0

That only enables AdGuard Home, and does not enable the option "AdGuard Home Handle Client Requests". In this way, when VPN is enabled, DNS requests will still go to the DNS server which set up in VPN profile.