  Chirally stacked $N$-layer graphene is a semimetal with $\pm p^N$
band-touching at two nonequivalent corners in its Brillioun zone. We predict
that an off-resonant circularly polarized light (CPL) drives chirally stacked
$N$-layer graphene into a Floquet Chern Insulators (FCIs), a.k.a. quantum
anomalous Hall insulators, with tunable high Chern number $C_F=\pm N$ and large
gaps. A topological phase transition between such a FCI and a valley Hall (VH)
insulator with high valley Chern number $C_v=\pm N$ induced by a voltage gate
can be engineered by the parameters of the CPL and voltage gate. We propose a
topological domain wall between the FCI and VH phases, along which perfectly
valley-polarized $N$-channel edge states propagate unidirectionally without
backscattering.
