With the advancement of green hydrogen production technology, power-to-ammonia (P2A) has emerged as a pivotal approach for consuming large-scale renewable resources. However, the inherent intermittency of wind and solar resources leads to a spatial and temporal mismatch between supply and demand, rendering effective integration within a single region challenging and necessitating cross-regional collaborative planning. To address this, we propose a coordinated planning model for a multi-regional ammonia industrial system (MAIS) that leverages the integration of a hydrogen supply chain (HSC) and power grid (PG), termed HSC-PG-MAIS. During the modeling of the HSC, we developed a novel hydrogen truck transportation model that allows trucks to serve as both hydrogen storage and transportation resources. Furthermore, considering the cooperative relationships among ammonia industrial systems in different regions, we proposed a Nash bargaining method based on the magnitude of interactive value contributions to equitably allocate the cooperation costs and benefits of the MAIS. Finally, real data from Shandong Province in China is used to validate the effectiveness and significance of the proposed model and strategy. The results indicate that the proposed model can effectively reduce the overall operating costs of the system and enhance its flexibility, providing valuable insights into exploring the collaborative potential of large-scale renewable resources across regions.