  We resolve the potential-restriction problem in K/G inflation by introducing
nonminimal coupling. In this context, Higgs field successfully drives inflation
satisfying CMB observations while enhancing curvature perturbations at small
scales, which in turn accounts for primordial black holes (PBHs) and scalar
induced gravitational waves (SIGWs). We then uncover the effect of the
non-canonical kinetic coupling function in more detail and study its the
observational constraint. Besides, we also give the gauge invariant expression
for the integral kernel of SIGWs, which is related to terms propagating with
the speed of light. Finally, the non-Gaussian effect on PBH abundance and SIGWs
is studied. We find that non-Gaussianity makes PBHs form more easily, but its
effect on the energy density of SIGWs is negligible.
