Nonlinear control laws are presented for input-constrained, multiple-input, multiple-output processes, whether their delay-free part is minimum or nonminimum phase. This study addresses the nonlinear control of input-constrained processes by exploiting the connections between model-predictive control and input-output linearization. The continuous-time control laws involve the solution of constrained optimization problems online. They minimize the error between controlled outputs and their reference trajectories, subject to the input constraints. Their application and performance are illustrated using numerical simulation of two chemical reactors that exhibit nonminimum-phase behavior.