Don Luis de Santa María Nanacacipactzin, also known as Cipac, was the last tlatoani ("king") of the Nahua altepetl of Tenochtitlan,[1] as well as its governor (gobernador) under the colonial Spanish system of government.

The previous ruler Cristóbal de Guzmán Cecetzin having died in 1562,[2] Nanacacipactzin was installed on September 30, 1563, and ruled until his death on December 27, 1565.

In January 1564, the viceroyalty passed a law requiring the Tenochca to pay 14,000 pesos in annual tribute, as well as a large payment in corn.

Nanacacipactzin resisted this demand, and faced a number of Spanish-backed lawsuits as a result, even being arrested for three days in September 1564 for failing to secure agreement to the new payments.

It appears his birth name was simply Cipactli "alligator", and the "mushroom" element was added as a nickname,[5] possibly due to a perception that he was ineffective in resisting Spanish tribute demands.