We study the large-time behavior of global energy class ( \(H^1\) ) solutions of the one-dimensional nonlinear Schrödinger equation with a general localized potential term and a defocusing nonlinear term. By using a new type of interaction Morawetz estimate localized to an exterior region, we prove that these solutions decompose into a free wave and a weakly localized part, which is asymptotically orthogonal to any fixed free wave. We further show that the \(L^2\) norm of this weakly localized part is concentrated in the region \(|x| \le t^{1/2+}\) and that the energy ( \(\dot{H}^1\) ) norm is concentrated in \(|x| \le t^{1/3+}\) . Our results hold for solutions with arbitrarily large initial data.