Starting with OS X El Capitan 10.11.4, you can take the files you created in other apps and import them into Notes app. Notes app can import files with file format of txt, rtf, rtfd, html and enex. To start importing files on your Mac, select from Notes menu File > Import Notes.
enex is Evernote XML Export format. Apple is obviously targeting Evernote users as it grows Notes’ capabilities and adoption. Imported notes however might look different, and features not supported by Notes will be removed during import. Nevertheless, direct import support is a more robust solution than using AppleScript to get enex files into Notes.