5 HNIO + 4 KMnVIIO4 + 6 H2SO4 5 HNVO3 + 4 MnIISO4 + 2 K2SO4 + 6 H2O

This is an oxidation-reduction (redox) reaction:

4 MnVII + 20 e- 4 MnII (reduction)

5 NI - 20 e- 5 NV (oxidation)

KMnO4 is an oxidizing agent, HNO is a reducing agent.