  The "failed Kondo insulator" CeNiSn has long been suspected to be a nodal
metal, with a node in the hybridization matrix elements. Here we carry out a
series of Nernst effect experiments to delineate whether the severely
anisotropic magnetotransport coefficients do indeed derive from a nodal metal
or can simply be explained by a highly anisotropic Fermi surface. Our
experiments reveal that despite an almost 20-fold anisotropy in the Hall
conductivity, the large Nernst signal is isotropic. Taken in conjunction with
the magnetotransport anisotropy, these results provide strong support for an
isotropic Fermi surface with a large anisotropy in quasiparticle mass derived
from a nodal hybridization.
