  We study the implications of the LHC Higgs signals on the Higgs mixing in the
next-to-minimal supersymmetric standard model (NMSSM). The Higgs couplings can
depart from their values in the standard model (SM) due to mixing effects.
However the Higgs signal rate in the WW and ZZ channels can remain close to the
SM values, as observed at the LHC, even if the SM-like Higgs boson with a mass
near 125 GeV has a large singlet component. This allows to get a sizable
enhancement in the Higgs to diphoton rate through the charged-higgsino loop
contribution, as well as a sizable reduction of the Higgs to bb and tautau
rates through the mixing effects, with little deviation in the WW and ZZ signal
rates from the SM prediction. We find that an enhancement of diphoton signals
by a factor of 1.5 or more, and also a reduction of bb and tautau signals by a
factor of 0.5, can be obtained in the region of parameter space consistent with
the constraints on the higgsino mass parameter and the singlet coupling to the
Higgs doublets, which determine the Higgs mixing.
