When Indonesia's new president, Prabowo Subianto, assumes office in October he'll preside over the world's biggest nickel reserves and is widely expected to continue policies that have led to a global price slump for the battery metal and stainless steel ingredient.

The Southeast Asian nation accounted for more than half of global nickel production last year, but volume is only part of the story.

Plentiful ore, cheap labor and low-cost electricity from power plants burning price-capped coal have helped Indonesia flood the world market with nickel at prices that sharply undercut competitors mining the metal...