The era of multi-messenger astronomy has unlocked new probes of physics, allowing natural experiments to be carried out on matter at extremes unattainable using terrestrial experiments. Neutron stars, and their mergers, are natural sites to seek probes of nuclear physics, as these compact objects contain the densest matter in the universe. I will discuss multi-messenger astrophysical observables from the point of view of nuclear physics constraints. In particular I will highlight resonant shattering flares (RSFs), which can provide strong constraints on the nuclear symmetry energy parameters of nuclear matter, comparable to those obtained by terrestrial nuclear experiments, such as those found in dipole polarizability and neutron skin thickness measurements.