Cu2IS-II + 8 HNVO3 2 CuII(NVO3)2 + S0 + 4 NIVO2 + 4 H2O

This is an oxidation-reduction (redox) reaction:

2 CuI - 2 e- 2 CuII (oxidation)

S-II - 2 e- S0 (oxidation)

4 NV + 4 e- 4 NIV (reduction)

Change the oxidation states