Highly flexible, piezoresistive nanocomposites have recently been of interest to researchers due to their versatility in sensing applications. These materials are fabricated by combining a flexible polymer with conductive nanofillers. One such polymer used as a matrix is the polydimethylsiloxane (PDMS) elastomer. Its biocompatibility, environmental friendliness, chemical inertness, and extreme flexibility make PDMS an excellent candidate for use in a wide range of high strain sensing applications. Carbon nanotubes (CNTs) are a great candidate for fillers in piezoresistive nanocomposites due to their superior electrical properties, leading to numerous studies investigating their use in piezoresistive materials for sensing applications. However, conventional nanocomposite fabrication methods using elastomers are often time consuming, requiring the creation of a mold for casting. In this regard, additive manufacturing (3D printing) of polymers, using a 3D printer to allow the deposition of uncured or partially cured thermoset polymer, has become an attractive technique for quickly and efficiently creating nanocomposite sensor samples. In this study, a PDMS-CNT nanocomposite is fabricated via a modified 3D printer, using a formulation allowing for free standing deposition of the uncured material into 3D shapes. The inclusion of CNTs provides this material with piezoresistive properties and makes it an excellent option for sensing applications. The free-standing material allows for simple manufacturing and reduces the amount of wasted material and fabrication time. The sensing function of the material and its durability were verified via static and cyclic compressive tests. The sensing mechanism is further studied via in situ micromechanical testing in a scanning electron microscope (SEM) to visualize the changes in alignment, positioning, and orientation of the CNT leading to the piezoresistive properties.