I'm sorry to disappoint you, but I don't think human sacrifice had anything to do with the Aztecs staying in power; they dominated Mesoamerica for 100 years. Colonists likely propagated stories of ritual killings because it was an effective way to justify their brutal conquest. You might want to take a look at this book called A Land So Strange by Marc Simmons for more information about what really went on during the Spanish invasion; he talks extensively about how Spaniards deliberately exaggerated the importance of human sacrifice in order to demonize native peoples and justify their own conquests.
First of all, Aztec power was mostly shaped through alliances with other nations. Secondly, human sacrifice probably didn't help Aztecs stay in power considering the Spanish conquered them quickly enough after arriving on their land. It doesn't seem like human sacrifice helped Aztecs stay in power considering they apparently used children for sacrifices often. All of the above reasons make it hard to conclude that human sacrifice helped maintain power or not because we would have to know
Explanation:
In other cultures north of Mexico, such as the Maya and Zapotec civilizations who flourished contemporaneously with the Aztecs, human sacrifice was largely a public event where the elites practiced rituals with nobles and rulers of other kingdoms. In Tenochtitlan, however, not only were the masses generally excluded from ceremonies involving human sacrifice but most victims came from lower social classes and were ritually killed in large numbers by Aztec warriors.
