2 HMnVIIO4 + 5 HNIIIO2 2 MnII(NVO3)2 + HNVO3 + 3 H2O

This is an oxidation-reduction (redox) reaction:

2 MnVII + 10 e- 2 MnII (reduction)

5 NIII - 10 e- 5 NV (oxidation)

HMnO4 is an oxidizing agent, HNO2 is a reducing agent.