In this study, we investigate the chaotic motion of double-walled carbon nanotubes (DWCNTs) with fluid by dealing with the effects of nonlinearities. The governing equations of the system are derived and solved by the variation method with Galerkin’s technique. A chaotic phenomenon occurs when the top Lyapunov exponent of the system becomes positive. Referring to the results of the computations of the largest Lyapunov exponent, we examine and discuss the effects of some parameters, such as flow velocity, driving frequency, and load amplitude, on the chaotic motion of the nonlinear system. These parameters play an important role in determining whether or not chaotic motion will occur on the system. Moreover, these parameters can be used to control the chaos of DWCNTs conveying fluid.