To prepare the seasoning, add the following ingredients to a small bowl: chili powder, salt, sweet paprika, garlic powder, onion powder, ground cumin, dried oregano and ground black pepper. Mix with a fork and set it aside.
Add butter to a saucepan and melt it over medium heat. Add the onions, carrots and red bell peppers. Sauté for about 3 minutes or until the onions are translucent.
Add the garlic, kale or spinach, and shredded cooked chicken. Sauté to help warm up the chicken, for about a minute over medium heat.
Add the prepared seasoning. Mix to coat and cook for about 30 seconds.
Add water and mix to combine. Cook while mixing frequently until the water has evaporated. Add sour cream and mix. Allow to simmer/cook for about a minute. We don’t want the mixture to be too wet because the extra moisture can make the tortillas soggy.
Remove from the heat and set it aside
Spray a 9×13 (quarter sheet pan) with oil.
When it comes to arranging the tortillas, we want to do it in a way where the meat mixture will be completely covered by the tortillas on all sides.
Arrange 8 of tortillas on the sheet pan first making sure they are overlapping/shingling one another and there aren’t any open gaps/areas. Also, be sure the tortillas are hanging over on all of the sides of the sheet pan (this will allow for them to be folded over a bit to help seal the tacos). Add the meat mixture and distribute it out evenly. Then, top it with the shredded cheese. Finally, add the remaining 4 tortillas making sure to mostly place them in the center (again making sure there aren’t any open gaps/visible areas). Fold the sides over and try to gently push it down to help hold its shape (if it doesn’t hold too well, that’s ok. Just be sure it’s folded down once we place the baking sheet on top).
Spray the tops of the tortillas with more avocado oil. Place a same size baking sheet over the top making sure the sides of the tortillas are folded in. Also, add an oven-safe heavy weight on top of the baking sheet (I used a cast iron skillet). Finally, carefully transfer it to the oven (bottom second rack) and bake for 20 minutes.
Carefully, remove the heavy weight and the top baking sheet and bake for an additional 15-20 minutes or until the top and bottom are golden brown and crispy.
Remove and allow to rest for 5-10 minutes before cutting into it.