Please read the documentation that i linked. It clearly says:
Installation
npm i --save @nextcloud/vue
I don’t know where you found the command, but the nextcloud-vue package is marked as deprecated on the npmjs.com page so this is clearly outdated.
The package also does not contain .vue files, it contains the compiled components. Please read the documentation on how to use them.
Also note that i have updated the usage example in my previous comment. Always import the components you want to use individually, never use a generic import from @nextcloud/vue. Why can be read in this thread: How to deal with @nextcloud/vue bloat?