Atomic Units:
Bazooka: (
http://www.imfdb.org/images/thumb/a/ac/Civ5_bazookaidle.jpg/600px-Civ5_bazookaidle.jpg) recolored to the standard uniform color (same as infantry)
Rocket Artillery: That I am unsure about. I will need to talk to you about that later
Anti-tank Gun:
Use the generic tank destroyer but repaint it to a more forest green color and add an aztec symbol on the side
Marine: The generic US marines are actually the same uniform that the standard Mexican soldier wore during the Atomic era. The only real reskin you need for them is to change their helmets to a darker shade of green (
https://forums.civfanatics.com/attachments/upload_2020-11-3_16-29-20-jpeg.574096/)
Mobile SAM: A fairly good mix.
Reskin the Spanish one (
https://forums.civfanatics.com/attachments/upload_2020-10-31_12-3-38-jpeg.573729/) an add an aztec symbol on the side
Paratrooper: One of these should make a good start:
Comparing mexican paratrooper images to the images here, I think generic 3 is the best fit. Just recolor it to look more like the dutch uniform (the semi-dark green)
https://forums.civfanatics.com/attachments/upload_2020-10-31_11-43-28-jpeg.573719/
Tank: Can use any of these, appropriately recolored.
Medium Tank Generic One, painted a darker shade of green with aztec symbol on the side of the turret
Bomber: Can use any of these, appropriately recolored.
Bomber generic recolored and with symbol
Fighter: German Units for Aztecs?
Actually, they used a more american version plane! They used the P-47D Fighter 'Thunderbird', but the closest thing I could find on Civ 5 was actually on your extra units mod (the P-51 Mustang)
Helicopter Gunship: Uses a Soviet model, which after WW2, it seems the Aztecs would tend to change allegiances to someone who would put pressure on the USA.
Sounds good to me! Just recolor it a bit and add aztec symbols to it
Atomic Bomb: I plan on using the B-29 model that the game usually uses, but with some obnoxiously painted war bird covering the plane.