In this proceeding, we discuss the finite-size scaling analysis of the order parameter related to the chiral phase transition in QCD with two massless quarks. We use data obtained in lattice QCD calculations performed with highly improved staggered quarks (HISQ) for a range of light quark masses, $1/240 \leq m_\ell/m_s \leq 1/27$ for different spatial volumes ($N_\sigma$) on Euclidean lattices with temporal extent $N_\tau=8$, satisfying $3\,N_\tau \leq N_\sigma \leq 10\,N_\tau$.
We observe that infinite volume extrapolated data
for the order parameter agree reasonably well with the expected $O(2)$ scaling behavior even for
physical ratios of the light-to-strange quark mass
ratio. We quantify deviations from asymptotic
scaling and perform a detailed analysis of the
influence of
finite-size effects in terms of temperature and quark masses at a fixed lattice cutoff. This is crucial for improving the reliability of the infinite-volume extrapolated estimate of the chiral order parameter and for a more precise determination of chiral phase transition temperature from direct Lattice QCD simulations.