I believe you are referring to what the parts catalog calls a "spring-holder," Nissan part number:
44220-31G11. Check the link provided and refer to part code "44020H":
https://www.nissanpartsdeal.com/parts-l ... am=441_C01
FYI, if you want to replace the rest of the springs and hardware, Rockauto.com has rear drum hardware kits (they don't contain the "spring-holder," though) for $5 and they cover both sides.