Q: ipad ios6 camera kit doesn't support nikon d3200? ios5 did.

Have you checked in your Nikon's settings that the pictures are being named in the standard 8 character naming convention?  For the CCK to read and download the pictures, they should be named something like DNS_0001

Unfortunately the same is true for the Nikon D600. Pictures taken with full resolution won't import using the camera connection kit with IOS6. I use .jpg highest resolution and fine quality. Jpg Pictures taken with medium resolution (13.5mpx) import just fine.

To solve the problem for the Nikon D600 I have to completely close the Photo App, which is used to import photos. Double Press the button on the IPad to show recently used apps. Press on the Photo App icon and hold until the the icon gets a red minus mark and starts to "wobble". By clicking the red minus the app icon (and with it some states that hinder the photo import) disappear. After that connecting the camery connection kit and importing my Nikon D600 full resolution picture works again.

See also:

Nikon D600 .jpg's are not imported, is there a limit for the resolution?