  We present an analysis of the chemical compositions in high-redshift
galaxies, with a focus on the nitrogen-enhanced galaxies GN-z11 and CEERS-1019.
We use stellar models of massive stars with initial masses ranging from 9 to
120 Msol across various metallicities to deduce the chemical abundances of
stellar ejecta for a few light elements (H, He, C, N, O). Our study reveals
insights into the chemical processes and elemental synthesis in the early
universe. We find that Population III stars, particularly at initial fast
equatorial rotation and sampled from a top-heavy initial mass function, as well
as stars at Z=10^{-5} with moderate rotation, align closely with observed
abundance ratios in GN-z11 and CEERS-1019. These models demonstrate log(N/O) =
-0.38, log(C/O) =-0.22 and log(O/H) + 12 = 7.82 at dilution factors of f =
20~100, indicating a good match with observational data. Models at higher
metallicities do not match these observations, highlighting the unique role of
Population III and extremely metal-poor stars in enhancing nitrogen abundance
in high-redshift galaxies. Predictions for other abundance ratios, such as
log(He/H) ranging from -1.077 to -1.059 and log{(^{12}C/^{13}C)} from 1.35 to
2.42, provide detailed benchmarks for future observational studies.
