There are various types of NAND Flash available. Bare NAND chips, SmartMediaCards, DiskOnChip.
SmartMediaCards are bare NAND chips covered by thin plastic. They are very common in digital cameras and MP3 players. The card itself contains nothing smart at all. It gets smart by software.
DiskOnChip is NAND Flash with additional glue logic as a drop in replacement for NOR Flash chips. The glue logic provides direct memory access to a small address window, which contains a boot loader stub, which loads the real boot code from the NAND device. The logic contains also control registers for the static NAND chip control lines and a hardware ECC generator.