Heat olive oil in a skillet over medium heat. Cook onions until caramelized. About 15 minutes.
Combine chicken, green chiles, onions and 1/2 creamy ranchero sauce together in a bowl. Reserve remaining sauce for serving.
Press pizza dough into the bottom of a 12-inch cast iron skillet.
Spread 1 package of the tomatillo sauce onto the pizza dough. Sprinkle mozzarella cheese on top. Top with the creamy ranchero chicken mixture. Sprinkle with Mexican cheese blend.
Bake the pizza in the preheated oven for 15 - 20 minutes or until cheese is melted and bubbly.
Remove the pizza from the oven, allow to set for 5 minutes. Sprinkle with fresh cilantro. Slice and serve. If desired, serve remaining creamy ranchero sauce and remaining package of tomatillo sauce on the side for dipping the pizza crust.