No, unfortunately, the developer of NKRemote didn't release a version of the product that can be run on a Linux system. However, it seems that you can use the camera mentioned on your system. To do this, you just need to search and download an application that can handle this device. In this matter, I suggest you take a look at F-spot or Digikam.
You can try installing any Windows-based applications on a Linux machine by using Wine. You can download this by accessing the download center from your Linux OS. After you installed Wine, visit the application's review page on Software Informer, download the Windows installer package and run it under Wine. You might encounter compatibility errors, but this is the only way to use this with your Nikon D90.