A new method for sensing a spectral hierarchy, quantum chaos, chaotic diffusion, dynamical stabilisation in atomic systems in the intense laser field in the multi-photon regime is developed. New method is based on QED perturbation theory approach to calculating multi-photon, above threshold ionization cross-sections, Focker-Plank evolutionary equation for studying quantum diffusion phenomena, Fedorov interference stabilisation model. It is at first found availability of the spectral hierarchy and separately quantum-chaotic range (satisfying to the Wigner distribution) in spectrum of multi-photon ionization for magnesium. It is discovered the phenomenon of chaotic diffusion in the multi-photon regime for this atomic system in a laser field. It is at first proposed consistent theoretical approach to modelling the dynamical stabilisation effect for atomic system in an intense laser field and theoretically predicted the cited effect in atom of neon in laser field with intensity ~1014 W/cm2 in an excellent agreement with experiment. Presented theory of studied phenomena is the physical basis for construction of the new nano-atomic elements and devices, including quantum Carnot engine, single-atomic lasers, quantum computers elements etc.