Sterile neutrinos have been proposed as resolutions to a variety of open questions in physics, such as neutrino oscillation anomalies, the nature of dark matter, and origins of neutrino masses. A variety of models posit the existence a Heavy Neutral Lepton (HNL), a GeV-scale, sterile neutrino which can decay to well-understood Standard Model particles. HNL production from tau neutrinos and the HNL's subsequent decay would produce a unique double-bang signature in the IceCube detector, enabling a novel search for GeV-scale HNLs at atmospheric neutrino energies. Event reconstruction of these double-bangs is adapted from the high-energy astrophysical tau neutrino reconstruction, to address the difficulty of reconstructing low-light events more common at these lower energies. This poster presents a first estimate of the IceCube DeepCore sensitivity to this signature, outlining an event-selection scheme which takes advantage of the characteristic topology of the HNL production-decay events in combination with ML and traditional methods.