Nuclear star clusters are dense and compact stellar systems, with sizes of a few parsecs, found at the centers of many galaxies. Their formation is thought to be closely connected to the assembly history of their host galaxies, and astronomers think that these clusters contain important clues about how galaxies formed and evolved over cosmic time. Recent studies suggest that different formation pathways may operate in late- and early-type galaxies, but the dominant mechanisms and their dependence on galaxy morphology remain unclear. While most observational studies have focused on early-type

We present, for the first time, model spectra of single-age, single-metallicity stellar populations computed with the E-MILES evolutionary synthesis code incorporating an environment-dependent, variable galaxy-wide initial mass function (gwIMF). This gwIMF, calculated using the GalIMF code, is rooted in the integrated galactic initial mass function (IGIMF) theory, which predicts IMF variations as a function of the star formation rate and the metallicity. By coupling these two codes, we generated a comprehensive library of single-burst stellar population spectra uniquely sensitive to gwIMF