2 CrIIO + 2 HNVO3 Cr2IIIO3 + 2 NIVO2 + H2O

This is an oxidation-reduction (redox) reaction:

2 NV + 2 e- 2 NIV (reduction)

2 CrII - 2 e- 2 CrIII (oxidation)

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