Start by preparing the creamy avocado sauce. In a blender, combine half of a medium avocado, sour cream, fresh lime juice, cilantro leaves, kosher salt, and a splash of water. Blend everything until smooth and creamy, stopping to scrape down the sides as needed. Taste and adjust seasoning if necessary, then refrigerate to let the flavors meld while you prepare the taco filling.

In a large skillet, heat 2 tablespoons of avocado oil over medium heat. Once hot, add chopped onions and sauté for about 3-4 minutes until they soften and become translucent. Next, add the lean ground turkey and half of the taco seasoning. Cook, stirring frequently, for about 6-8 minutes until the turkey is browned and fully cooked through; it should be no longer pink.

To the skillet with the cooked turkey, stir in the canned black beans, green chiles, and the remaining taco seasoning. Add a splash of water to help bring everything together. Allow the mixture to simmer for about 15 minutes, stirring occasionally, until heated through and the flavors meld beautifully.

Preheat your oven to 425°F (220°C). While the oven is heating, lay the fajita-sized flour tortillas on a baking sheet lined with parchment paper. Lightly sprinkle shredded Monterey Jack cheese down the center of each tortilla. Fill each tortilla generously with the turkey mixture, then fold them over. Finally, spray the tops lightly with cooking spray or brush with a little avocado oil.

Place the baking sheet in the preheated oven and bake the tacos for about 10-12 minutes. Keep an eye on them; they are ready when the tortillas are crispy and golden brown.

Once baked to perfection, remove the tacos from the oven and let them cool for a minute. Serve them warm, alongside the creamy avocado sauce.