Most likely the CVT, yeah. By it's nature the CVT has a small whine sound to it. There's a few things that can also contribute to it as well.
-Check the transmission fluid level. If it's overfilled the fluid can be getting aerated which can cause additional whine or make it louder.
-Wrong fluid being used. Nissan usually recommends NS-2 or NS-3 (or equivalent) in their CVTs (check the manual, newer models tend to use NS-3), and it's what comes in them from the factory. Since it's a newer vehicle I'd doubt this to be a problem, but something to bear in mind whenever you change the fluid.
-Problem or wear issue with the CVT tensioner. Again, unlikely as it's a newer vehicle, but there can always be a defect.
-Check recall alerts/notices, or ask a (reliable) dealer if there's any known issues.
-Have a diagnostic ran at a dealer or mechanic with the appropriate equipment to see if the computer is picking up any problems or throwing error codes.
If your engine has a turbo they can whine as well, however the sound is usually louder/more pronounced and typically only kicks in during acceleration or under heavy load. I don't think the Kicks has a factory turbo version, though.
There's some other things that can cause a whine under the hood, but I'd start with these as they're the most common.