3 NaNVO3 + 16 NaOH + 4 Cr2IIIO3 3 NaN-IIIH2 + 8 Na2CrVIO4 + 5 H2O

This is an oxidation-reduction (redox) reaction:

3 NV + 24 e- 3 N-III (reduction)

8 CrIII - 24 e- 8 CrVI (oxidation)

Change the oxidation states