Nepal is keenly watching India’s ongoing parliamentary elections, where the presumed victory of Hindu nationalist Narendra Modi is raising questions about the future of the Himalayan nation’s transition from a Hindu monarchy to a secular democracy.

In 2006, Nepal agreed to abolish its 240-year-old Hindu monarchy as part of the Comprehensive Peace Accord ending a decade-long Maoist insurgency. Modi’s Bharatiya Janata Party (BJP), then the main opposition party in India and leader of the National Democratic Alliance, wasn’t happy with the change at the time, and BJP nostalgia for its neighbor’s official Hindu identity has lingered. ...