[2] At the time of Nimlot's rule, the Kushite king and pharaoh Piye was launching a campaign of conquest against Middle and Lower Egypt (c. 729–728 BCE).

This volte-face caused Piye's immediate reaction: he marched northward and besieged Hermopolis until Nimlot's capitulation.

After the conquest of the city, Nimlot had to give rich tributes to Piye as a compensation for his defection, including a horse and a precious sistrum; Piye, a great lover of horses, was also extremely disappointed to find Nimlot's stables in poor state, and harshly scolded him for the neglect.

[3][4] After Nimlot's submission, the situation turned more favorable for Piye, and he managed to defeat Tefnakht's coalition.

On Piye's Victory stele, Nimlot is one of the four Delta kings subdued by the Nubian conqueror – the others are Iuput II of Leontopolis, Osorkon IV of Tanis and Peftjauawybast of Herakleopolis; among the quartet, Nimlot is depicted standing instead of kneeling,[5] since Piye chose him as interlocutor, while the others were considered "impure", due to the fact that they ate fishes.