  This paper explores the interplay of momentum transfer and nonlinear optical
processes through moir\'e phenomena. Momentum transfer plays a crucial role in
the interaction between photons and matter. Here, we study stacked metasurfaces
with tailored dispersion and rotated against each other with varying twisted
angles. The stacking introduces interlayer interactions, which can be
controlled by the relative angle between metasurfaces, significantly enriching
the resulting response compared to the single layer counterpart. By focusing on
second-harmonic generation (SHG) from these twisted metasurfaces, we delve into
the realm of nonlinear moir\'e photonics. Through experimental observations, we
unveil the emergence of intricate far-field SHG radiation patterns, showing
their effective tuning by varying the twisted angles. These findings offer a
fresh perspective to explore nonlinear wavefront shaping through moir\'e
phenomena, opening new avenues for nonlinear information processing, optical
steering, and nonlinear optical switching.
