  We successfully grew single crystals of Si- and Ge-square-net compounds of
NbSiSb and NbGeSb whose excellent crystalline quality are verified using
single-crystal x-ray diffraction, rocking curves, scanning and transmission
electron microscopies. Since these two compounds share major crystallographic
similarity with the topological nodal-line semimetals of ZrSiS family, we
employ density functional theory (DFT) calculations and magnetotransport
measurements to demonstrate their band structures as well as the electron
scattering mechanisms. DFT calculations show that the fermiology shows strong
anisotropy from the crystallographic c-axis to the ab-plane and weak anisotropy
within the ab plane, which is consistent with the strong anisotropic
magnetotransport behaviors. Following the Kohler's scaling rule we prove that
similar interband and intraband electron-phonon scattering mechanisms work in
both the NbSiSb and NbGeSb compounds. The study of electronic transport
mechanism in the presence of external magnetic field renders deep insight into
topological behavior together with it's Fermi surface, and the high similarity
of crystallography and strong difference in band structures between the present
single crystals and that of ZrSiS family provides the possibility to tune the
band structure via element doping
