There is only one file type that uses the .NCER extension:
Nitro Cell Resource File
An NCER file is a graphic resource data file used by various games for the Nintendo DS handheld console. It contains information about the arrangement of graphic tiles that make up images used in the game.
NCER files are part of the Nitro file system, which is a collection of resource files used by Nintendo DS games to define images, textures, audio, and text. The files are not meant to be viewed or edited by a user, instead, they are referenced by the Nintendo DS game.
However, Nintendo DS game ROMs may be dumped to computers by nostalgic gamers in order to play the games on their computers. Users can then rip NCER files and other Nitro resource files from the ROMs to view and modify the files.
NOTE: The Nintendo DS device was a handheld gaming console released in 2004.
Updated: September 29, 2019