This study computationally investigates the effects of carbon-based nano additives on the tensile mechanical characteristics of nanoporous polyethylene through classical molecular dynamics simulations. For this purpose, graphene flakes, fullerenes and carbon nanotubes are employed as filler units within the nanoporous polymer structure which is built numerically by applying Voronoi based modelling approach. All the nano fillers, among which the graphene flakes provide the best performance, are shown to enhance the mechanical properties including Young's modulus, ultimate tensile and yield strengths. A remarkable improvement on the toughness of the specimens is achieved by graphene flakes owing to the higher load-transferring interface between the graphene and the polymer matrix. Furthermore, it is demonstrated that the carbonaceous nano fillers significantly increase the structural integrity of the nanoporous polyethylene. By this way, the possibility of obtaining thermodynamically stable nanoporous structures composed of ultrathin ligaments is presented, which heralds the nano-cellular structures with the ultra-high specific surface area to be utilized with superior performance in several applications including thermal insulation and filtering.