  Unconventional superconductors represent one of the fundamental directions in
modern quantum materials research. In particular, nodal superconductors are
known to appear naturally in strongly correlated systems, including cuprate
superconductors and heavy-fermion systems. Van der Waals materials hosting
superconducting states are well known, yet nodal monolayer van der Waals
superconductors have remained elusive. Here, using low-temperature scanning
tunneling microscopy (STM) and spectroscopy (STS) experiments, we show that
pristine monolayer 1H-TaS$_2$ realizes a nodal superconducting state. By
including non-magnetic disorder, we drive the nodal superconducting state to a
conventional gapped s-wave state. Furthermore, we observe the emergence of
many-body excitations close to the gap edge, signalling a potential
unconventional pairing mechanism. Our results demonstrate the emergence of
nodal superconductivity in a van der Waals monolayer, providing a building
block for van der Waals heterostructures exploiting unconventional
superconducting states.
