Among 3d transition metal intercalated transition-metal dichalcogenides (TMDCs), Fe_xNbS₂ has been found to possess unique current pulse-induced resistive switching behaviors and tunable antiferromagnetically ordered states, both of which show an abrupt change across x=1/3 doping. Currently, how the low-energy conduction electrons and local magnetic moment in this system contribute to such coupled effects remains unclear. Using angle-resolved photoemission spectroscopy (ARPES), we report several doping and orbital selective correlation effects across the ⅓ doping level. There is massive electronic structure reconstruction originating from the Fe sub-lattice, together with a doping sensitive charge order and spectral decoherence. What’s more, the electronic structure suggests a mixed dimensionality of this system as opposed to the common notion of a "2D" magnet in intercalated TMDCs.  Finally, we discuss the possibility for revealing potential novel magnetic and electronic properties in other intercalated TMDC systems from a strongly correlated point of view, complementing existing weak coupling descriptions.