In this paper, we propose a hybrid classical-quantum approach to study the electron transport in strongly confined nanostructures. The device domain is made of an active zone (where quantum effects are strong) sandwiched between two electron reservoirs (where the transport is considered highly collisional). A one dimensional effective mass Schrödinger system is coupled with a drift-diffusion model, both taking into account the peculiarities due to the strong confinement and to the two dimensional transversal crystal structure. Interface conditions are built preserving the continuity of the total current. Self-consistent computations are performed coupling the hybrid transport equations with the resolution of a Poisson equation in the whole three dimensional domain. To illustrate this hybrid strategy, we present simulations of a gate-all-around single-walled Carbon Nanotube Field-Effect Transistor.