We present JWST/MIRI MRS spectroscopy of three Seyfert AGN in which we compare their nuclear Polycyclic Aromatic Hydrocarbons (PAHs) emission with that of star-forming regions. This study, for the first time, investigates local luminous Seyferts (Lbol > 1044.46 erg/s) over a wide wavelength range (4.9-28.1 μm) using sub-arcsecond angular resolutions. We find that a suite of PAH features are present in the innermost regions (~0.45′′ at 12 μm; in the inner ~142-245 pc) of each of these Seyfert galaxies. An analysis of the nuclear PAH properties is completed through comparison of the observed ratios with PAH diagnostic model grids derived from theoretical spectra. Based on the three galaxies observed, the nuclear regions of AGN lie at different positions of the PAH diagnostic diagrams, whereas the star forming regions are concentrated around the average values of star forming galaxies. Furthermore, we find that the nuclear PAH emission mainly originates in neutral PAHs while, in contrast, PAH emission originating in the star forming regions favors ionized PAH grains. In the nuclear region of AGN-dominated galaxy NGC 6552 the observed PAH ratios indicate the presence of larger-sized PAH molecules compared with those of the star forming regions. We therefore conclude that this provides evidence that AGN have a significant impact on the ionization state (and probably the size) of the PAH grains on scales of ~142-245 pc.