With an intermediate resolution between light and electron microscopes, the commercial lab-based X-ray microscope (Xradia Ultra 810), here referred to as nanoCT, is a versatile new tool for the characterization of biological samples and for bioinspired materials research. With its mechanical in situ testing, the nanoCT is suited for structural characterization of complex 3D samples down to 50 nm resolution with and without loading. It allows for the observation of microstructural changes as a function of time and mechanical load. With its low energy X-ray source (Cr source, 5.4 keV) and Zernike phase contrast, the setup is ideal for analyzing low-density samples, such as polymers and soft tissues. To demonstrate its potential, samples of centric diatoms (Thalassiosira) and seed hairs from thistle (Cirsium vulgare) were characterized for their inner structure and in situ tensile and indentation nanoCT scans were carried out for the thistle hairs and diatoms, respectively.