Chitosan nanoparticles have received a lot of attention in recent years due to their beneficial properties as healthy supplement to supply bioactive substances in the food industry and nutrition. The purpose of this study was to investigate the influence of cChitosan nanoparticles (CsNPs) as nutritional stimulus at the early feeding for the Nile tilapia (Oreochromis niloticus) fry on the growth performance, feed efficiency, and histomorphological health of the liver and intestine. Graded levels of CsNPs ( 0.05, 0.1, 0.2, 0.4, 0.8, and 1.6 g kg⁻¹ diet) were added to the basal diet, and each experimental diet was fed to three groups of fish with an approximate weight of (0.86± 0.04 g) for 70 days. The experimental study concluded that CsNPs 0.1 and 0.2 g kg⁻¹ diets resulted in significantly higher final weight (FW), weight gain (WG), specific growth rate (SGR), energy efficiency ratio (EER), and survival (S%) compared to the control group (P <0.05). However, the protein efficiency ratio (PER) increased but did not differ substantially (p < /del>P> 0.05) between the control and other treatments. The intestine of the Nile tilapia fryies showed that the villi height increased in the diet-fed groups of 0.1 g CsNPs kg^-1 diet, 0.2g CsNPs kg^-1 diet, and 0.4 g CsNPs kg^-1 diet, while the highest villi length was recorded in the group of 0.2 g CsNPs kg^-1 diet. The group fed on (0.2 g CsNPs kg^-1 diet) demonstrated normal healthy intestinal walls and branched villi with intact enterocytes comprising the intestinal villi . Histopathological structure of the Nile tilapia liver in fryies fed with CsNPs revealed that the control group had congested blood sinusoids and fatty vacuolization of hepatocytes,. whereas the 0.2g CsNPs kg^-1 diet group displayed normal hepatocytes with slight lymphocyte infiltration. Findings of the current study illustrated the positive effect of dietary supplementation of 0.2g kg^-1 of chitosan nanoparticles which is considered as a promising compound in improving the growth performance, feed efficiencies, and an increase in villi length to facilitate the absorption process in the intestinal Nile tilapia (Oreochromis niloticus) fry.