We experimentally demonstrate the formation of spatial supercontinuum and of spatial frequency combs in nonlinear photonic lattices. This process results from multiple four-wave mixing initiated by launching two Floquet-Bloch modes into a one-dimensional lattice. The dynamics of the waves is sensitively dependent on the transverse momentum difference between the two initial modes: when this momentum difference is commensurable with the lattice momentum the waves evolve into a frequency comb, whereas when it is incommensurable the waves evolve into a supercontinuum of spatial frequencies.