In this paper, we present a direct computational method for solving the higher-order nonlinear differential equations by using collocation method. This method transforms the nonlinear differential equation into the system of nonlinear algebraic equations with unknown shifted Chebyshev coefficients, via Chebyshev-Gauss collocation points. The solution of this system yields the Chebyshev coefficients of the solution function. The method is valid for both initial-value and boundary-value problems. Several examples are presented to illustrate the accuracy and effectiveness of the method by the approximate solutions of very important equations of applied mathematics such as Lane-Emden equation, Riccati equation, Van der Pol equation. The approximate solutions can be very easily calculated using computer program Maple 13.