Owing to the large quantity of pesticides utilized conventional pesticide formulations can have numerous negative environmental impacts such as side effects on human health and pest resistance development. Using nano-pesticide formulations can minimize the quantity of pesticides used, thereby lowering pest control costs, and environmental contamination. This work used self-emulsifying and solidification technology to convert chlorpyrifos, emamectin benzoate, and beta-cyfluthrin to solid nano-dispersions, all of which were examined for their properties and efficacy against the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.). During the preparation of the formulation mixture, solid nano-dispersion particles with sizes ranging from 7 to 400 nm were developed. With the design of the nano-formulation, there were variations in the active ingredient, carrier, surfactant, and pesticide concentration types. The type of active ingredient, carrier, surfactant, and pesticide concentration varied with the nano-formulation design. The nano-formulation with 1 to 5% pesticides, 8% a combination of Nonyl phenol ethoxylated surfactant (Unitop 100) mixed with Geronol surfactant (FF4), and sucrose as a carrier indicated the best polydispersity index, Z-average, and biological activity. Moreover, the surfactant and solvent content in the solid nano-dispersion formulation was lower than in conventional pesticide formulations. Based on the LC50 values, chlorpyrifos, emamectin benzoate, and beta-cyfluthrin solid nano-dispersions were more toxic (LC50 values were 0.17 and 0.07 for emamectin benzoate, 4.61 and 3.61 for beta-cyfluthrin, and 10.06 and 6.74 mg/L for chlorpyrifos after 24 and 48 h of treatment, respectively) than their conventional formulations (LC50 values were 0.85 and 0.36 for emamectin benzoate nano-dispersion, 19.19 and 15.30 for beta-cyfluthrin nano-dispersion, and 27.01 and 26.17 mg/L for chlorpyrifos - nano-dispersion after 24 and 48 h of treatment, respectively) against S. littorralis under laboratory conditions. Under field conditions, chlorpyrifos, emamectin benzoate, and beta-cyfluthrin in nano-dispersion formulations were more effective against cotton leaf worms than the same insecticides in commercial formulation. Thus, nano-formulations could be recommended in pest control where they avoid organic solvents and reduce surfactants, control costs, and environmental pollution.