An ideal third-order nonlinear optical material, which can efficiently absorb and refract light over a broad spectral range, is of both fundamental and technological signiï¬�cance as it enables many helpful functionalities in photonics. However, the optical nonlinearities are rather weak due to their perturba- tive nature and are limited to electronic resonances, thus restricting the response to a narrow spectral range. A charge-coupled donor-acceptor material pair can enhance the nonlinear optical response and cir- cumvent the narrow spectral range limitation. However, such studies on potential material pairs remain largely unexplored. Here, we report the experimental observation of ultrafast third-order nonlinear optical response spanning the entire visible-to-near-infrared (400–900 nm) region in single-wall-carbon-nanotube (SWCNT)–VSe₂ nanohybrid in the strong coupling regime, enabled by efficient charge transfer. Compared to control systems, the measured nonlinear absorption and refraction of the nanohybrid show unprece- dented or many-fold enhancements. Further, our density functional theory and Bader-charge analysis show the strong electronic coupling of the nanohybrid in which the electrons are transferred from VSe₂ to SWCNT, veriï¬�ed by steady-state and time-resolved photoluminescence measurements. The physics of the ultrafast nonlinear optical response is well captured by our ï¬�ve-level rate-equation model both qualita- tively and quantitatively. Using the nanohybrid, we design a liquid cell-based optical limiter with an order of magnitude better device performance parameters, such as the optical limiting onset (2.5–8.0 mJ cm⁻²) and the differential transmittance (0.42–0.62), compared to several other benchmark optical limiters in the femtosecond regime.