ABSTRACT:  A systematic asymptotic connection between the nonclassical spherical harmonic approximation (NSHA) and the simplified PN (SPN) equations is developed for linear particle transport with nonclassical free-path distributions. Starting from the nonclassical transport equation posed in extended phase space, the NSHA moment system is analyzed under diffusion scaling and asymptotically reduced to macroscopic transport equations. This analysis shows that the diffusion-limit reduction of NSHA(N) yields a hierarchy of coupled second-order equations constituting a nonclassical SPN system, with transport coefficients expressed explicitly in terms of moments of the free-path distribution. The derivation is carried out in detail for N = 1 and N = 3, recovering the nonclassical diffusion (SP1) and SP3 equations through a systematic asymptotic procedure. The resulting equations retain full sensitivity to the underlying free-path statistics and reduce exactly to the classical SPN equations in the exponential free-path limit. The general SPN structure is then established for arbitrary odd order N, and consistency with the explicit SP1 and SP3 limits is demonstrated. The analysis is further extended to anisotropic scattering by retaining the full angular dependence of the scattering kernel within the NSHA framework. Corresponding anisotropic SP1 and SP3 equations are derived, and the general anisotropic SPN form is obtained. In all cases, the macroscopic equations arise directly from asymptotic elimination of the free-path variable, without phenomenological closure assumptions. These results establish NSHA as a unified theoretical foundation for nonclassical SPN models and clarify their connection to diffusion-based transport approximations in media with nonexponential free-path statistics.