Nuvola implements Media Player Remote Interface Specification (MPRIS 2). Doesn't ring a bell? It's a must-have technology that various applets and media indicators use to control media playback over DBus.
To enable Media Player DBus Interface, open Preferences dialog from the Menu button and
toggle Media Player DBus Interface option on.
The built-in media player applet can be found among notifications under the date & time button.
Click Date & Time button.
The applet shows track metadata (album art, track title, and artist).
You can control media playback (skip to the previous track, toggle play/pause, skip to the next track).
You can click the notification itself to show Nuvola window.
Media Player Indicator Extension
Although the built-in media player applet is good enough, I recommend checking out the awesome
Media Player Indicator extension
(originally created by Jean-Philippe Braun, now developed by Jason Gray).