The Nissan Qashqai comes with a factory fitted immobiliser and keyless entry, but not an alarm.
My recommendation is the Cobra AK4615 CAN-BUS upgrade alarm which works flawlessly with the factory remote.
Expect a hidden digital battery back-up siren and horn honk as standard.
Below is a video and some photos to help show how the alarm functions in the Qashqai:
Current Shape Nissan Qashqia can out in 2014
Cobra Alarm Installation Details
Own an older Model Nissan Qashqai?
If you have the previous generation Qashqia the AK4615 also works.