Plant-based meat analogues have gained much interest in recent years and are considered a sustainable approach to overcoming protein malnutrition that is caused by increasing population numbers and decreasing animal-based meat production day by day. Plant-based meat alternatives were produced by applying several techniques, including high-moisture extrusion, twin-screw extrusion, electrospinning, and the application of soft-matter physics, but 3D food printing gave better results in terms of texturization and nutritional profiles. In this research, 100 g of soy protein isolate (SPI) was mixed with distilled water (30%, w/w) and oyster mushroom (Pleurotus ostreatus) powder was added at 4, 8, and 12% to obtain three samples. All the samples were blended to obtain a homogenous paste. An 80 mL syringe of extrusion-based 3D printer was filled with developed paste samples and the printing process was carried out to produce 3D chicken-nugget-shaped soy meat with 1.6 mm of nozzle size at room temperature. The printing performance, microstructure, texture, moisture distribution, and rheological properties were all assessed. The inks enriched with SPI showed good viscoelastic properties with pseudoplastic behavior. The mushroom powder gave a fibrous texture to the final product obtained. The addition of 8% mushroom powder gave the best results in terms of texture and rheological properties, as compared to all the samples under study. The sample with 4% mushroom powder had a less fibrous texture and the sample with 12% mushroom powder gave a more fibrous texture, but the product became too hard and was disliked.