In this paper, a new cascaded multi modular chaotic logistic map (CMM-CLM) is proposed. The bifurcation diagram for the proposed CMM-CLM is very complex and it has strong chaos properties. The strong chaos leads to a very high Lyapunov exponent values. Based on the proposed CMM-CLM, a new robust physical layer security for the interleaved NOMA based on the multilayers concept (ML-I-NOMA) with the iterative decoder has been introduced. The analysis of the proposed ML-I-NOMA cryptosystem is studied in the both encrypted and non-encrypted image transmission. The main contribution of this paper is to prove that, the different layer effect has a slight performance change compared with the bandwidth consumption. Finally, the simulation results clarified that, the proposed MLI-NOMA achieves 50% and 75% bandwidth efficiency at 2 and 4 layers with an excellent visual quality metric in the correct detection. In addition, the security analysis reveals that, the proposed ML-I-NOMA cryptosystem has large key space and good key sensitivity, and its entropy approaches to the idea value. Hence, the proposed ML-I-NOMA cryptosystem based on the CMM-CLM can strongly resist traditional cipher attacks.