Answer
Nitrogen has a formal charge of +1 because it has 4 bonds. So the charge of the whole molecule is +1.
Work Step by Step
Formal Charge (FC) = [number of valence electrons] - [number of non-bonding electrons] - 1/2 [shared electrons]
FC (nitrogen) = 5-0-4 = +1
FC (oxygen) = 6-4-2 = 0
FC (hydrogen) = 1-0-1 = 0
