Start by brining the chicken legs in 20 ounces of water and 1 ounce of kosher salt.
To make the brine, first put the salt and half the water in a small saucepan. Heat until the salt has dissolved. Then, add the remaining water to help cool it down.
Put the chicken legs in a ziplock bag. Pour the cooled brine into the ziplock bag with the chicken, making sure it's completely submerged. Then refrigerate for at least 30 minutes or up to a day.
Next, add the parsley, garlic, red wine vinegar, olive oil, salt, and black pepper to the bowl of a food processor. Process until finely minced. Add the red pepper flakes and pulse a few more times. Pour into a small bowl and set aside.
In a small bowl, add the garlic powder, onion powder, baking powder, paprika, salt, and black pepper. Mix until completely combined and set aside.
Preheat the Air Fryer to 400 degrees.
Remove the chicken from the brine and pat dry with a paper towel. Add the chicken, olive oil, and seasoning blend to a medium bowl. Mix with your hands or use a large spoon to coat the chicken.
Place the chicken legs in the air fryer basket and cook for 10 minutes.
Carefully flip the chicken and cook for another 8-10 minutes or until the chicken has reached 165 degrees.
Remove the chicken from the air fryer and allow it to rest for 5 minutes. Top with the Chimichurri sauce, and enjoy!