  In the ferrimagnetic nodal-line semiconductor Mn$_3$Si$_2$Te$_6$, colossal
magnetoresistance (CMR) arises below $T_\mathrm{c}=78$ K due to the interplay
of magnetism and topological nodal-line fermiology. The Berry curvature
associated with the topological nodal-line is expected to produce an anomalous
Nernst effect. Here, we present sizable anomalous Nernst signal in
Mn$_3$Si$_2$Te$_6$ below $T_\mathrm{c}$. In the low-magnetic-field region where
CMR is most apparent, the scaling ratio between the Nernst signal and
magnetization is significantly enhanced compared to that in conventional
magnetic materials. The enhanced Nernst effect and CMR likely share the same
mechanisms, which are closely linked to the nodal-line topology.
