Matt Fritz has these simple set of free wargamesrules for recreating the Siege of Tenochtitlan. He uses them with his students — a great idea for both wargaming and learning! It inspires me to try similar things in my classroom.
Jeffe Koppe describes his efforts in building an Aztec Gateway.
In the Jungle is an interesting set of rules for conquistador vs aztec games. It’s played on a gridded board and is supposed to simulate a group of “lost” conquistadors trying to find their way to a temple without falling victim to sacrifice.