NiAl-based alloys are emerging as promising high-temperature materials, owing to their excellent properties such as a high melting point, exceptional oxidation behavior, and low density. However, low fracture toughness and low ductility at room temperature limit the application area. A eutectic microstructure consisting of fine cellular-lamellar phases can improve these properties. Our newly developed alloy Ni_30.6Al₃₆Cr_31.4Mo₂ (at.%) in combination with electron beam powder bed fusion (PBF-EB) exhibits this favorable microstructure due to the eutectic composition and the high cooling rates present in additive manufacturing. The elevated process temperature achievable by PBF-EB can be used for an in-situ heat treatment. Consequently, spinodal decomposition and discontinuous precipitation occur and therefore change the microstructural composition. In addition, modifying material characteristics such as material density, phase volume fraction, phase thickness, and grain size is achievable by controlling the process parameters and thus the thermal conditions. In this contribution, we present dense, crack-free specimens of the eutectic Ni_30.6Al₃₆Cr_31.4Mo₂ alloy processed by PBF-EB and a detailed microstructural study including chemical composition analysis. Moreover, the experimental results are validated by CALPHAD calculations and literature data. Considering these findings, we offer a deeper understanding of the relationship between energy input and microstructure and therefore, the possibility of tailoring the microstructure.