3 HNVO3 + Cr2IIIO3 + 7 KOH 3 KNIIIO2 + 2 K2CrVIO4 + 5 H2O

This is an acid-base reaction (neutralization): HNO3 is an acid, KOH is a base.

This is an oxidation-reduction (redox) reaction:

3 NV + 6 e- 3 NIII (reduction)

2 CrIII - 6 e- 2 CrVI (oxidation)

Change the oxidation states