Yes. You can simply twist Suzy's hat clockwise to turn on the nightlight at any time. Continuing to turn clockwise will increase the light's brightness. Turning anti-clockwise will dim the nightlight, all the way down to completely off.
Alternatively, you can customise the Soothing Sequence in Suzy's settings in the BleepBleeps app so that the music is muted. This means when you push down Suzy's hat (to start the Soothing Sequence) the lights will animate but no music will be heard.