Welcome to INTEL forum. The DE0-Nano Board belong to Terasic. It would be better if you could contact Terasic for enquiry related to Terasic board. https://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=12&No=20
Please accept my apologies for not being able to assist you fully as this is out of my expertise.
Update, received answer from terasic:
"The J4 connector is used to connect the externel Blaster download cable for programming the CPLD device on the DE0-Nano kit. It cannot be used for the external device programming. "