CuIIS-II + 2 HNVO3 Cu0 + 2 NIIO + H2SVIO4

This is an oxidation-reduction (redox) reaction:

CuII + 2 e- Cu0 (reduction)

S-II - 8 e- SVI (oxidation)

2 NV + 6 e- 2 NII (reduction)

CuS is an oxidizing agent, CuS is a reducing agent, HNO3 is an oxidizing agent.