Zn0 + 4 HNVO3 ZnII(NVO3)2 + 2 NIVO2 + 2 H2O

This is an oxidation-reduction (redox) reaction:

Zn0 - 2 e- ZnII (oxidation)

2 NV + 2 e- 2 NIV (reduction)

Change the oxidation states