The Nonlinear Structural Materials Module augments the mechanical capabilities of the Structural Mechanics and MEMS Modules by adding nonlinear material models, including large strain plastic deformation capabilities. When the mechanical stress in a structure becomes large, certain nonlinearities in the material properties force the user to abandon linear material models. This situation also occurs in some operating conditions, such as high temperature. The module adds elastoplastic, viscoplastic, creep, and hyperelastic material models. User-defined material models based on strain-invariants, flow rules, and creep laws can easily be created directly in the user interface with the built-in constitutive laws as a starting point. Material models can be combined as well as include multiphysics effects. The included tutorial models illustrate this by showcasing combined creep and elastoplasticity, thermally induced creep and viscoplasticity, fluid-structure interaction, and elastic waves.