Enhancement of nodal line-driven anomalous Nernst effect in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi mathvariant="normal">F</mml:mi> <mml:msub> <mml:mi mathvariant="normal">e</mml:mi> <mml:mn>3</mml:mn> </mml:msub>

The anomalous Nernst effect (ANE), a thermoelectric (TE) phenomenon that generates a voltage perpendicular to both temperature gradients and spontaneous magnetization, has attracted interest in energy harvesting applications. However, its practical implementation remains limited by low TE conversion efficiency. Here, we investigated strain-induced enhancement of ANE in a $\mathrm{D}{0}_{3}$-type Heusler compound $\mathrm{F}{\mathrm{e}}_{3}\mathrm{Si}$ using first-principles calculations. The transverse TE conductivity improved approximately 50-fold compared to the unstrained condition, due to the $4%$ compressive strain loading on the (111) plane. The electronic structure analysis revealed that the improvement stems from the nodal line shift closer to the Fermi energy under compressed strain. Strain engineering offers a promising approach to manipulate the topological electronic structure, such as nodal lines and Weyl nodes, which are the origin of ANE, and thus enhance TE performance. These results suggest new design principles for high-performance TE devices.