  In heavy-ion collisions, understanding how light nuclei species are produced
can provide insight into the nature of hadronic interactions in extreme
conditions. It can also shed light on understanding the matter-antimatter
asymmetry and dark matter searches in astrophysical processes. To investigate
the production mechanism of light nuclei such as deuteron, triton, and
helium-3, we use a naive coalescence afterburner coupled to the well-known
$``$A Multi-Phase Transport model" (AMPT). We focus on studying the production
of light nuclei in central Au+Au collisions at different center of mass
energies ($\sqrt{s_{_{\rm{NN}}}}$ = 19.6, 39, and 200 GeV) and in Pb+Pb
collisions at $\sqrt{s_{_{\rm{NN}}}}$ = 2.76 TeV, at mid-rapidity. We generate
events with the string melting version of AMPT, and feed the information of the
nucleons with spatial and momentum conditions into the coalescence afterburner.
Our study reports differential and integrated yields in transverse momentum
($p_{\rm{T}}$) of the light nuclei in different center of mass energies. We
also estimate the coalescence parameters ($B_A$) as a function of $p_{\rm{T}}$
and collision energy for (anti-)deuterons, tritons and helium-3s for Au+Au and
Pb+Pb collisions, which are compared to other light nuclei production studies.
All results are compared with measurements from the STAR and ALICE experiments.
