It's a 64k by 1-bit Dynamic RAM.
Not much value these days - over 30 years old. The date code may be 1982 week 8.
I designed similar devices into products in 1983.
This is not the NEC part but probably pin compatible 64K DRAM datasheet.
EDIT - As pointed out by Lawrence I misread the part number and added a 4. This is a 64k by 1 DRAM that is a bit earlier than the 64kx4 part.