  It has been recently established that a nonlinear valley current could be
generated through traveling a surface acoustic wave (SAW) in two-dimensional
Dirac materials. So far, the SAW-driven valley currents have been attributed to
warping Fermi surface or Berry phase effect. Here, we demonstrate that tilt
mechanism can also lead to a nonlinear valley Hall current (VHC) when
propagating SAW in materials with the tilted Dirac cone placed on a
piezoelectric substrate. It's found that the nonlinear VHC exhibits a
$\sin\theta$ dependence on the orientation of tilt with respect to SAW. In
addition, this tilt-induced nonlinear acoustic VHC shows independence on the
relaxation time, distinguishing from the contributions from the Berry phase or
trigonal warping. Remarkably, the magnitude of the nonlinear acoustic VHC from
tilt mechanism in the uniaxially strained graphene is two orders larger than
those reported in MoS$_2$ stemmed from the Berry phase effect and the warping
effect.
