Combine the seasonings in a small bowl and then set aside.
In a large bowl, toss the chicken thighs with half of the olive oil and half of the spice blend, ensuring they are evenly coated. Allow them to sit at room temperature for at least 15 minutes so that the flavors can penetrate the meat.
Meanwhile, rinse the potatoes and pat dry. Cut them in half or quarters depending on their size, then place them in a separate bowl and drizzle them with the remaining olive oil. Season with the remaining spice blend. Toss the potatoes to ensure they are well coated with the oil and seasoning.
Place potatoes, cut side down in the bowl of your Ninja Foodi Air fryer. Select the sear/saute function and cook on high heat until they have formed a nice golden crust on the bottom. Flip the potatoes.
Now place the grill insert over the tops of the potatoes. Place the seasoned chicken thighs, skin side up on the grate, making sure to leave some space between them for proper air circulation. Depending on the size of your air fryer, you may need to cook them in batches.
Set the Ninja Foodi to Air Crisp mode. Set the temperature to 400°F and cook the chicken thighs for 20-25 minutes. The exact cooking time may vary depending on the size and thickness. Test the thickest part of the thigh with a meat thermometer to ensure the internal temperature reaches 165°F for safe consumption.
Once the chicken thighs and potatoes are cooked to perfection, carefully remove them from the air fryer. Allow the chicken to rest for a few minutes to retain its juiciness before serving.