A hierarchical two-layer control structure is designed with robust Model Predictive Control. The system at the upper level is described by a Wiener model, while the systems at the lower level, which represent the fast actuators dynamics, are described by general nonlinear models. The proposed control structure guarantees steady-state zero error regulation for constant reference signals and allows one to largely decouple the control design phase at the two levels while still guaranteeing the overall stability under mild assumptions.