The interest in doped and functionalized graphene nanomaterials for various applications is growing due to the development of new and simple production and treatment methods. Amongst the techniques used to treat graphene nanomaterials dry methods like plasmas or ion beams are of particular interest. In this work a low temperature plasma technique is used to incorporate nitrogen atoms into the carbon network of graphene sheets. In order to gain a better understanding of such processes material analysis techniques (NEXAFS and XPS) were combined with the results coming from molecular dynamics simulations and plasma know-how. The results show that the plasma post treatment of graphene nanowalls can be regarded as a balance between vacancy formation, functionalization, doping and crosslinking. Moreover, MD simulations provided insight into fundamental mechanisms like the formation of different bonds due to the interaction of the surface with different kind of species with variable kinetic energy. This can help to improve different types of doping/functionalization techniques using energetic species: the study reveals for example the role of N2+ species, the kinetics of vacancy formations depending on type and energy of the species, the formation of amines or graphitic nitrogen, and the role of impurities such as NHx species.