Today, the development of multifunctional and versatile packaging materials based on green ingredients has received a lot of attention from researchers and consumers due to their biodegradability, biocompatibility, sustainability, and renewable nature of biomaterials. These emerging packaging materials in addition to increasing the shelf life of food products (active packaging), informs the consumer about the freshness and spoilage of the product in real-time (smart packaging). The limitations reported for biopolymers-based packaging, such as hydrophilicity and poor mechanical resistance, can be modified and improved by combining biopolymers with various materials including nanomaterials, cross-linkers, bioactive compounds, and other polymers. Consequently, the use of innovative, high performance, and green bio-nanocomposites reveal a promising opportunity to replace conventional non-biodegradable petroleum-based plastics. Likewise, interest in making polymeric bio-nanocomposites for active and smart packaging purposes has been increased in response to a global request for more effective and safe food packaging systems. There are various factors affecting the quality of bio-nanocomposites, such as biomaterials type, additives like nanoparticles, foods type, storage conditions, and the approaches for their preparation. In this review paper, we aimed to discuss the main challenges of the techniques commonly employed to prepare polymeric bio-nanocomposites, including casting, melt mixing (extrusion), electrospinning, and polymerization techniques. The casting has captured scientists’ interest more than other techniques, due to the easy handling. The extrusion methods showed a more industrial approach than other techniques in this field. The electrospinning process has attracted a lot of interest due to the production of fibrous membranes, able to encapsulate and stabilize bioactive molecules. The polymerization technique shows less interest amongst scientists due to its complicated conditions, its reaction-based process and the use of toxic and not green reactants and solvents. In conclusion, all techniques should be optimized based on relevant specific parameters to obtain bio-nanocomposites with notable mechanical behaviors, barrier and permeability properties, contact angle/wettability, uniform structures, low cost of production, environmental-friendly nature, migration and penetration, and biodegradability features.