Nitrogen has a formal charge of +1 because it has 4 bonds instead of 3. And Chlorine has a charge of -1 due to the extra electron. Both charges cancel each other to give an overall charge of zero.
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 (chlorine) = 7-8-0 = -1 FC (hydrogen) = 1-0-1 = 0