Observation of the decays ${\chi }_{cJ}\to n{K}_S^0\bar{\mathrm{\Lambda }}+c\mathrm{.}c\mathrm{.}$

By analyzing $4.48\times {10}^8$ $\psi (3686)$ events collected with the BESIII detector, we observe the decays ${\chi }_{cJ}\to n{K}_S^0\bar{\mathrm{\Lambda }}+c\mathrm{.}c\mathrm{.}$ ($J=0$, 1, 2) for the first time, via the radiative transition $\psi(3686) \to \gamma \chi_{cJ}$\mathrm{.}Thebranchingfractionsaredeterminedtobe$(6.67 \pm 0.26_{\rm stat} \pm 0.41_{\rm syst})\times10^{-4}$,$(1.71 \pm 0.12_{\rm stat} \pm 0.12_{\rm syst})\times10^{-4}$,and$(3.66 \pm 0.17_{\rm stat} \pm 0.23_{\rm syst})\times10^{-4}$for$J=0$, 1, and 2, respectively.