To start, before building an action or a droplet to convert from Raw, you need at least either the RAW plugin, or the photoshop lightroom plugin, depending on the version of Photoshop. I assume you have the plugin installed on your Photoshop. See: Adobe - Adobe Photoshop CS4: Digital camera raw file support.
A better choice would be having the Nikon Capture NX
, that give you the option to work on the native RAW format from Nikon.
Once you have installed a plugin to manage RAW format files you can record an action or droplet to automate the process. If youj want more automation, you set an action first, as a batch process to do action on a single file, then build a droplet on the action batch file. A droplet will give more automation, since droplets can be activated by dropping a folder of images onto that specific Droplet Process, and they will apply the batch process to all the files contained in the folder.
The way you build the batch action depends much on the version of Photoshop you are using and on the plugin used. Here an example using Adobe PS CS2 and camera Raw plugin: Raw Format Workflow with Adobe Bridge .
The action can be saved using the recorder, so that the procedure will de quite instinctive. See the tutorials below for step-by-step instructions.
See also:Adobe - tutorial : Lights, camera, action!Batch Processing Camera RAW images in Photoshop CSCreating a Droplet : Adobe Photoshop TutorialBatch Processing Camera RAW images in Photoshop CS