This study aimed to investigate the effects of chitosan nanoparticles (C-NPs), spermine (Spm) as well as chitosan nanoparticles encapsulated spermine (C-Spm NPs) on growth, yield, chlorophyll, bioactive compounds, and capsaicinoids in chili pepper cv. Omiga F1 under saline stress conditions. Data indicated that the exogenous application of C-NPs, Spm, and C-Spm NPs alleviated the adverse effect of salinity on chili pepper plants and enhanced growth, yield, chlorophyll content, antioxidant enzymes activity superoxide dismutase (SOD), and catalase (CAT). The maximum values of these parameters were recorded when plants treated with C-Spm NPs at 1.5 mM. For GC/MS analysis, data revealed the presence of 22 active compounds whereas, the maximum area percent were, 1-Tetradecanol(CAS), Phenol,2,4-bis(1,1-dimethylethyl), 1-Heptadecene(CAS), 3-Eicosene,(E), (cis)2-nonadecene, and 5-Eicosene,(E). Regarding the capsaicinoids found in chili pepper, the main compounds identified among the capsaicinoids were capsaicin and dihydrocapsaicin. The maximum amount of capsaicin and dihydrocapsaicin were recorded when plants treated with C-Spm NPs at 0.5 mM. For the general taste of chili pepper, the Scoville heat unit (SHU) was calculated. Data indicated that plants treated with C-Spm NPs at 0.5 mM gave quite a high SHU related to higher contents of the capsaicinoids.