It appears that in 5.10.0-RC1, it is now required that names are unique across nodesets and sidesets:
ERROR: Duplicate names detected. The name 'bottom' was found for both SideSet 0 and NodeSet 0. Names must be unique over all types in a finite element model.
Can someone please explain the rationality for this? Within MOOSE (GitHub - idaholab/moose: Multiphysics Object Oriented Simulation Environment) we rely significantly on consistency in naming between nodesets and sidesets.