It seems you are looking for a way to change the orientation of your pictures while they are still in the camera. I do not know if Nikons provide such a feature, I believe none of the Canons that I owned over the years provided such an option.

But this is pretty easy to fix once you downloaded the pictures to your computer. The orientation is written as picture metadata to JPEG and raw files in EXIF format. A free EXIF editor like ExifTool can fix your images.

The orientation value stored in the pictures is a number, usually one of these four values:

• 1 when the top of the camera points up (the normal landscape position)
• 8 when the top of the camera points left (90 degree counter-clockwise rotation from normal landscape position)
• 3 when the top of the camera points down (camera upside down)
• 6 when the top of the camera points right (90 degree clockwise rotation from normal landscape position)

Note that these values indicate the rotation of the camera when the picture was taken. The image data is never rotated, the top of the image is always aligned with the top of the camera. See this page for graphics that illustrate this.

Using exiftool, you can check the orientation number stored in your pictures as follows:

exiftool -Orientation -n <imagename>

And to change the orientation value you can use this command:

exiftool -Orientation=<value> -n <imagename>

I hope this helps.