To investigate the interaction between N forms and Cu nanoparticles (CuNP) in maize plants (Zea mays L.) and its impact on plant growth, chlorophyll fluorescence, nutrient uptake, and soil properties, an experiment was performed in a greenhouse. The treatments were proportions of NO3-/NH4+ (100/0 and 50/50) and rates of CuNP (0, 25, 50, and 100 mg kg(-1)) applied in an acidic (pH 4.59) Spodosol soil deficient in Cu (1.3 mg kg(-1)) under a randomized complete block design. Plant development and rhizosphere and bulk soil properties were evaluated. The dry biomass production was the highest when the plants received N-NO3- and CuNP at 25 mg kg(-1) instead of a combination between NO3- and NH4+. The CuNP excess decreased the quantum efficiency of photosystem II and photochemical quenching, as well as increased the non-photochemical quenching in plants grown at 50/50 NO3-/NH4+. The accumulations of C, N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn were the highest in plants grown at N-NO3- combined with CuNP at 25 mg kg(-1), which were related to the highest rhizosphere soil pH, lowest availability of nutrients in the soil, and lowest soil electric conductivity. The highest NO3- availability was found in the rhizosphere soil, which was related to the highest rhizosphere soil pH. Nitrate supply improves the positive effects of CuNP on maize plants, stimulating the best plant growth, nutrient uptake, and rhizosphere environment. It is important to consider proportions of NO3-/NH(4)(+ )in plants even when nanoparticles are used.