This study investigates the microstructural and mechanical behavior of milled-sintered Ni-Al-Co-Cr-Cu-Mn-Ti high-entropy alloys (HEAs) using both CALPHAD-based thermodynamic modeling and experimental nanoindentation techniques. The elemental powders of the HEAs mechanically alloyed at three cycles of 5, 10, and 15 hours were sintered at temperature of 9000C, heating rate of 100 0C/min, pressure of 50 MPa, and holding time of 5 min. Predictive modelling of the strengthening phases was done using Thermo-calc. SEM-EDS and XRD used to characterize the microstructure, phase composition, and elemental distribution revealed a multiphase structure, dominated by BCC_B2 solid solution, FCC_L21 and intermetallic phases. Nanoindentation analysis used to characterize their mechanical properties at the nanoscale showed that the equiatomic alloy A, sintered at 900°C for 15 minutes, exhibited the highest hardness (HIT = 14.9 GPa) and elastic modulus (EIT = 234.47 GPa). Additionally, alloy A displayed the lowest indentation depth (923.431 ± 0.004 nm) at a load of 300 mN, with no pop-in effect observed. In contrast, the non-equiatomic alloy C exhibited the highest penetration depth (962.271 ± 0.005 nm) and displayed a pop-in effect under the same loading conditions.