Charge on Nitrogen in NCl3
First of all charge of atom is not well defined (maybe except AiM). Formal charge of both is zero, but that does not help us to understand chemistry. Above mentioned reaction shows that nitrogen is more negative, and if you do simple QM computation both Mulliken and NBO gives ~-.44 for N and ~+.147 for Cl. If you want to have a bit feeling about it, think that way: both have similar electronegativity but Cl is bigger so it's easier to polarize.