In the present study, the thermal performance of a modified solar still (MSS) system coupled with hybrid nanofluid (HNF) of titanium oxide (TiO2) and silicon oxide (SiO2) has been investigated theoretically based on energetic, exergetic, economic, and enviroeconomic assessment. The model of the MSS has been introduced using a new numerical technique of the Atangana-Baleanu fractional derivative. The fractional model of the MSS system is presented under various weather circumstances (winter and summer seasons) in Egypt to show the impact of HNF on the MSS output: temperatures, freshwater productivity, exergy, and energy efficiencies. The outcomes of the fractional model are contrasted to those derived from actual experimental data collected under varying climatic conditions in Upper Egypt. Numerical findings demonstrate specific consistency between the experimental results and the proposed model of the solar still (SS), with a percentage of error of 4.65% in freshwater productivity. Moreover, using hybrid nano enhances daily productivity in the summertime by 27.2% and in the wintertime by 21.7%, increasing efficiencies. Additionally, a comparative economic and environmental assessment has been investigated for all the proposed desalination systems without and with HNF. The findings found that the cost per liter of MSS was 44% lower than that of the conventional solar still (CSS) during the summer season. Using exergy and energy approaches, MSS reduced CO2 by 22% and 29.6% more during the winter.