This brief proposes a unified approach for generating chaos in -dimensional continuous-time affine systems, with 3, based on the normal form of chaotic systems and nonlinear control theory. A feedback-control law is designed to make a feedback linearizable system topologically conjugate to a reference chaotic system, thereby forcing the given system to become chaotic. Furthermore, if the relative degree of a given feedback unlinearizable system is not less than three and the corresponding internal dynamics of the system is input-to-state stable, then a feedback-control law can still be designed to drive a subsystem of such a controlled system topologically conjugate to a reference chaotic system, thereby generating chaos from that subsystem.