Please provide more context. "Nirmala Devi" is not a uniquely identifying name, and without additional information, it's impossible to provide an accurate biography. There are likely multiple individuals with that name. To help me give you the biography you're looking for, could you please tell me:

What is she known for? (e.g., a specific profession, field of study, activism, etc.) Where is she from? (e.g., which country or region) When was she active? (e.g., a time period or approximate birth year)

The more information you can provide, the better I can identify the correct Nirmala Devi and provide you with a relevant and accurate biography. Without these details, any biography I provide would be purely speculative and potentially about the wrong person.