The Spanish sources have been dominant on this for centuries, so it's great that you want to turn to indigenous perspectives.

It took a few decades for Aztecs to learn alphabetic writing, so we don't have sourced from the immediate conquest period nor from pre-colonial times. But there are important later works that still have strong connections to earlier native histories and traditions, some of them are luckily translated into English (I'll put a small selection at the end).

The main native sources we have on the conquest period and its direct aftermath come only a few decades afterwards – meaning that the main sources on this are by Spaniards like Cortés and Castillo. While Cortés mentions the Tlaxcala as probably his main allies, conquistadors generally downplayed the importance of native allies in the conquests, also in order to highlight their own roles.

Of course most pre-Hispanic sources (and many early colonial ones as well) were destroyed by the Spanish; and it would take some decades for Nahua - another term for "Aztec" I'm using here since "Aztec" was only popularised know the 19th century - to be sufficiently adapt at alphabetic writing and Spanish to produce writings.

The first generation of Nahua writers is seen to come up around the mid-16th century in connection with the famed Colegio de Tlatelolco, where they were schooled by the Franciscans. So that parts of Bernardino Sahagún's works were written by his Tlatelolca collaborators.

Around this time more traditional codices were also produced, using glyphs and images, which would focus more on pre-colonial history, colonial tributes etc. By the late 16th century major alphabetic chronicles and annals were written by native authors in Nahuatl and Spanish.

With all of this we have to keep in mind that all these native authors had sufficient background in European and Spanish knowledge that these permeated their writings. So it's almost impossible to speak of clear „native“ positions in this context.

Two main things to keep in mind then with Aztec sources: a) the Spanish victory would not have been possible without their native allies who made up the majority of their forces. And b) the Aztec Triple Alliance was dominated by the Mexica, but other groups within and outside of the alliance had their own strong local identifications- these would strongly influence their views of the Aztec-Spanish war.

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Instead of a big list it may be more helpful to list a few sources you may find interesting (could add more that are in Spanish):

• Mesoamerican Voices edited by Matthew Restall: It has good introductions for each section, and one section on the conquest period - with sources from the Nahua and other indigenous groups. This may be a good place to start as an overview.

• The Native Conquistador by Fernando de Alva Ixtlilxochitl, edited by Amber Brian et al. Translated very recently with comprehensive introduction. It's an action packed account of the siege of Tenochtitlan focusing less on Cortés and mostly on one of his main Acolhua allies called Ixtlilxochitl. Written by one of his descendants who is one of our main sources on the Acolhua ( part of the Triple Alliance), so he strongly takes their side. Students usually enjoyed reading this when I brought it to class.
  (Will try and add a bit about Sahagún later on)

Hope this helps!