A nonlinear control design strategy is proposed based on functional expansion (FEx) models. The controller is formulated as a linear controller with a series of correction terms to account for nonlinearities in the system. Case studies include discrete control of a copolymerization reactor, ideal and one-way decoupling control of a chemical reactor, and control of a bioreactor with complex dynamics. The nonlinear control laws are shown to provide superior performance compared to their linear counterparts, while maintaining, similar flexible design features.