The detection of coherent-neutrino nucleus scattering (CEvNS) opens a new window to study the fundamental properties of neutrinos and to probe physics beyond the Standard Model of Particle Physics. Given the very low recoil energies (eV – keV) predicted for this weak neutral-current process, it has only recently been observed experimentally. Favorably, due to the coherency of the interaction, the cross-section of CEvNS is typically 2 – 4 orders of magnitude larger than classical neutrino interactions, which leads to a dramatic miniaturization of neutrino detectors: instead of using multi-ton detector apparatuses, neutrino detection with compact devices of kg or even g in total mass is in reach. We have established a new experimental approach for a first measurement of CEvNS at a nuclear reactor – the NUCLEUS experiment. With dedicated cryogenic detectors, for which we have demonstrated world-record energy thresholds of ~20 eV, we will probe neutrino properties and scenarios for new physics at unprecedentedly low energies. In this seminar, I will give an overview of this young and growing research field, and present the status and physics potential of NUCLEUS.