The current study was carried out during 2020 and 2021 seasons on sweet pepper variety: Taison. Its objective was to assess the impact of coating fruits with a solution of nano-salicylic acid (Nano-SA) at 100 and 200 ppm, nano-chitosan (Nano-SC) at 125 and 500 ppm, salicylic acid (SA) at 200 ppm and chitosan at 500 ppm for 5 min, in addition to untreated fruits (control) during storage at 5°C for 35 days plus 2 days at 20°C (shelf life) on alleviating chilling injury and preserve fruit quality attributes. Results indicate that sweet pepper fruits treated with all postharvest treatments had significantly less fruit weight loss, retained their firmness, L* value, and ascorbic acid, alleviated chilling injury retained total antioxidants and total phenol and the overall appearance of fruits. Also, the lowest accumulation of carotenoids content during all storage period as compared with control. Fruits treated with Nano-SA at 100 ppm or Nano-SC at 125 ppm treatments were the most effective treatments in preserving all the quality attributes of fruits, and gave good appearance of fruits for 35 days without any decay or chilling injury, while Nano-SA at 200 ppm and Nano-SC at 500 ppm treatments gave a good appearance of fruits for 28 days at 5°C plus 2 days at 20°C, but Bulk-SA and SC treatments gave a good appearance of fruits for only 14 days at the same storage condition.