3 Cu2IO + 14 HNVO3 6 CuII(NVO3)2 + 2 NIIO + 7 H2O

This is an oxidation-reduction (redox) reaction:

6 CuI - 6 e- 6 CuII (oxidation)

2 NV + 6 e- 2 NII (reduction)

Cu2O is a reducing agent, HNO3 is an oxidizing agent.