  The observation of the light hybrid candidate $\eta_1(1855)$ by the BESIII
Collaboration brings great opportunities for advancing our knowledges about
exotic hadrons in the light flavor sector. We show that this observation
provides a crucial clue for establishing the $J^{P(C)}=1^{-(+)}$ hybrid nonet.
Based on the flux tube model picture, the production and decay mechanisms for
the $J^{P(C)}=1^{-(+)}$ hybrid nonet in the $J/\psi$ radiative decays into two
pseudoscalar mesons are investigated. In the $I=0$ sector, we find that the
SU(3) flavor octet and singlet mixing is non-negligible and apparently deviates
from the flavor ideal mixing. Since only signals for one isoscalar
$\eta_1(1855)$ are observed in the $\eta\eta'$ channel, we investigate two
schemes of the nonet structure in which $\eta_1(1855)$ can be either the higher
or lower mass state that strongly couples to $\eta\eta'$. Possible channels for
detecting the multiplets are suggested. In particular, a combined analysis of
the hybrid production in $J/\psi\to VH$, where $V$ and $H$ stand for the light
vector mesons and $1^{-(+)}$ hybrid states, may provide further evidence for
this nonet structure and finally establish these mysterious exotic species in
experiment.
