Answer
Formal charge on N is +1
Formal charge on O is -1.
Work Step by Step
Formal charge = number of valence electrons -
(number of nonbonding electrons + $\frac{1}{2}$ number of bonding electrons)
For nitrogen,
no. of valence electrons = 5
number of nonbonding electrons = 0
number of bonding electrons = 8
Hence, formal chargo on nitrogen = 1.
For oxygen,
no. of valence electrons = 6
number of nonbonding electrons = 6
number of bonding electrons = 2
Hence, formal chargo on oxygen = -1.
