Just a simple OAuth2 plugin so you can login to your WordPress site from Nextcloud, there is an option to add a login button on the WordPress login page and a shortcode so you can generate your own button. You can set what Nextcloud user groups get mapped to what WordPress user role and what page the users get redirected to on successful login. If you're using the External sites app in Nextcloud you can set the URL as www.example.com/wp-login.php?nc-sso=redirect and it will auto redirect the user to your Nextcloud install to login without them having to click the login button.
The plugin has been tested with Nextcloud 20.0.14 to 31.0.4.
If you have any problems please reach out on the support forum or directly here.
Note this isn't an official plugin from Nextcloud, it's just from someone that uses it with WordPress alot.