Nikon's new, in-house developed FX-format CMOS sensor featuring 20.8 effective megapixels,
http://imaging.nikon.com/lineup/dslr/d5/
Yup, the key word is developed as you have emphasized:
Nikon develops the sensor, a foundry manufactures it
Apple develops the A6, A7, A9, etc chip, a foundry manufactures it
AMD develops ATI graphics processors, a foundry manufactures them
nVidia develops GE Force processors, a foundry manufactures them
Porsche develops the Boxster/Cayman, a company called Valmet in Finland built them through 2011
Of the camera companies, only Canon and Sony actually physically make their sensors, and in Canon's case, only some of them.