The present work addresses the problem of chaos control in an electrostatic MEMS resonator. One of the unstable orbits immersed in the chaotic attractor is stabilized in order to produce a sustained oscillation of the movable plate composing the microstructure. The orbit is carefully chosen in order to produce a high amplitude oscillation. This approach allows the enhancement of oscillation amplitude of the resonator at a reduced control effort, since the unstable orbit already exists in the system. Parametric uncertainties in the model are considered and control laws are constructed using the technique of backstepping. Numerical simulations are carried out to confirm the validity of the developed control schemes and to demonstrate the effect of controlling orbits immersed in the chaotic attractor.