  We explore the magnetotransport and thermoelectric (Seebeck and Nernst
coefficients) properties of Mn3SnC an antiperovskite magnetic Nodal line
semimetal. Mn3SnC shows paramagnetic (PM) to concurrent antiferromagnetic
(AFM)/ferromagnetic (FM) transition at 286 K. The electrical resistivity and
Seebeck coefficient indicate the importance of electron magnon scattering in
the concurrent AFM/FM regime. We observed a large positive magnetoresistance
(MR) of 8.2 at 8 T field near magnetic transition, in the otherwise negative MR
behaviour for low temperatures. The electrical resistivity and MR show a weak
thermal hysteresis around the boundary of transition temperature and the width
of hysteresis decreases as magnetic field increases. Interestingly the Hall and
Seebeck coefficients change sign from positive to negative below the transition
temperature, highlighting the different scattering for holes and electrons in
this multi-band system. The Seebeck and Nernst signal exhibit two sharp
anomalies; one at the transition temperature and another at 50 K. The anomaly
at magnetic transition in the Nernst signal disappear at 8 T magnetic field,
owing to the reduction of magnetic fluctuation. A pseudo-gap near the Fermi
level produces an upturn with a broad minimum in the Seebeck signal.
