India’s largest power producer is looking to develop another massive nuclear project just weeks after announcing its entry into the sector, a sign that Prime Minister Narendra Modi’s expansion into atomic energy is gaining momentum. A venture between NTPC Ltd NSE 1.26 %., which relies mostly on coal to supply energy to the world’s fastest growing population, and India’s monopoly nuclear developer is in advanced talks with the government to develop two 700-megawatt reactors in the central state of Madhya Pradesh, according to people familiar with the matter, who asked not to be identified as the discussions aren’t public.