  We review the physics and some applications of photonic structures designed
for the realisation of strong $\textit{nonlinear chiroptical response}$. We pay
much attention to the recent strategy of utilizing different types of
$\textit{optical resonances}$ in metallic and dielectric subwavelength
structures and metasurfaces, including surface plasmon resonances, Mie
resonances, lattice guided modes, and bound states in the continuum. We
summarize earlier results and discuss more recent developments for achieving
large circular dichroism combined with the high efficiency of nonlinear
harmonic generation.
