Yes you are moving in the right direction. Here's what I found out.
NordPass offers these instructions for exporting its passwords: https://support.nordpass.com/hc/en-us/articles/360007646477-How-to-export-passwords-from-NordPass
Supposedly it will ask where to save the file so choose the Desktop or some other location you remember.
To import those passwords into the Passwords app: Import passwords from another app into Passwords on Mac - Apple Support
Yes you can do everything on your Mac. Provided that you use iCloud Keychain to synchronize your Mac, your iPad, and your iPhone, those passwords will migrate to those devices through iCloud. Make your passkeys and passwords available on all your devices with iPhone and iCloud Keychain - Apple Support explains how that works.
I am assuming you are using iCloud Keychain. If not, Set up iCloud Keychain - Apple Support explains.
Lastly... As I understand your original concern, you want to rid your Mac of NordPass and all its saved passwords. I suspect they are going to show up every time as a duplicate suggestion every time you use Safari Autofill. That is certain to be annoying, but I don't know of any better way to eliminate the duplicates other than to delete them methodically through the Passwords app. On the other hand, perhaps they won't be appearing as duplicates, in which case you're finished. I don't use NordPass so that's a question I cannot answer.
When you are happy with Safari's password organization and everything is working to your satisfaction, deleting the NordPass account is explained here: https://support.nordpass.com/hc/en-us/articles/360006668297-How-to-delete-my-NordPass-account. It includes some of the instructions regarding exporting your passwords prior to deleting the account.
Be sure to read its last paragraph:
"Please note that because Nord products' databases are interconnected, deleting only your NordPass account will not remove basic information, such as your email address, from Nord’s database if you have an existing NordVPN or NordLocker account. To delete all of your data, you must follow the full Nord Account deletion steps."
Bear in mind I don't use Nord products so I'm not sure if "deleting all of your data" is important or not.