how do you balance
I2 + HNO3 = HIO3 + NO2 + H2O

Using half-reactions:
1(I2) + 6(H2O) = 2(HIO3) + 10(H+) + 10(e-)
1(HNO3) + 1(e-) + 1(H+) = 1(NO2) + 1(H2O)

Multiplying the bottom by 10 (to cancel out the electrons) yields

1(I2) + 10(HNO3) = 2(HIO3) + 10(NO2) + 4(H2O)

which, upon double-checking it, it balanced.