Liquids and polymers confined down to nanometric scales can show a range of exotic behaviors, with broad relevance from engineering to biology. Significant progress in our understanding has been achieved in the recent years, driven in part by experimental efforts in the fabrication of nanofluidic devices reaching exquisite control over the degree of liquid confinement or by highly controlled measurements of the relaxation dynamics of thin polymeric films. However, transport dynamics in these sophisticated configurations is still probed by macroscopic and ensemble-averaged approaches, unable to reveal in a clear and direct manner sub-continuum transport effects. Here, we aim to bridge this gap by developing novel experimental approaches to directly visualize and quantify molecular motion in nanometrically confined liquids, focusing on polymeric liquid melts as model systems. To do so, we will combine single-molecule fluorescence microscopy techniques on fluorescently grafted polymer chains with transport dynamics in a spontaneouly spreading prewetting film (providing intrinsic molecular confinement), to tackle key long-standing questions on the role of confinement on molecular transport.