Definitely not. Pacific Rim has no connection to manga. It was conceived and brought to life specifically as a cinematic production with its own distinct storyline and universe.
The 'Pacific Rim Story' could potentially revolve around the unique ecosystems found along the Pacific Rim. It could tell of the diverse marine life, from the colorful coral reefs to the large whales that inhabit those waters. It may also include stories of the indigenous peoples who have lived in harmony with this environment for centuries, their traditions and their relationship with the land and sea. Additionally, it could cover modern-day issues like conservation efforts and the impact of climate change on the Pacific Rim.
It's a story of humans fighting against giant monsters from another dimension using huge robots. The robots are piloted by pairs of humans who need to have a mental connection to operate them effectively.
First, you need to study both universes thoroughly. Know the characteristics of the Jaegers, their pilots, and the kaiju in Pacific Rim. For Godzilla, understand his powers and his different forms. Then, come up with an interesting concept like a crossover battle or a team - up. Next, create engaging characters, whether they are new or existing ones from the two universes.