In this investigation, we study the behavior of a hybrid nanomaterial system combining chitosan-based tetrasulfonated copper phthalocyanine catalyst (Chit/Ts-CuPc) modified carbon screen-printed electrodes (CSPE) for the determination of nitrite and nitrate. Under optimal experimental conditions defined by cyclic voltammetry (CV) and square wave voltammetry (SWV) surveys, the functionalized CSPE exhibited significant catalytic activity towards nitrite and nitrate with a considerable enhancement of the cathodic-anodic peak currents. The Chit/Ts-CuPc nanocomposite enabled the sensors to have a broad linear detection range, which allows quantifying analytes at various concentrations, from 40 to 100 µM for nitrite and 1 to 10 µM for nitrate. Low detection limits (3Sb/m) have been achieved, which are 0.06 µM and 0.05 µM for nitrite and nitrate ions, respectively. Moreover, the proposed modified electrode showed its applicability by measuring the concentration of nitrite and nitrate ions with interfering species and in real water samples.