Make the Marinade: In a medium bowl, whisk together 1 1/2 tablespoons olive oil, lemon juice, garlic, rosemary, 3/4 teaspoon salt, and pepper.
Marinate: Add chicken thighs to the marinade and toss to coat. Refrigerate for at least 30 minutes.
Preheat: Heat your air fryer to 400°F (200°C) for 3–5 minutes.
Season Potatoes: In another bowl, toss the potato chunks with 1 tablespoon olive oil and 1/2 teaspoon salt.
Prep Chicken: Remove chicken from the marinade and pat the skin completely dry with a paper towel. Discard leftover marinade.
Arrange: Place potatoes in an even layer in the air fryer basket. Nestle chicken thighs on top, skin-side up, leaving space between pieces.
Air Fry: Cook at 400°F (200°C) for 12 minutes.
Flip: Open the basket, flip the chicken thighs once, and stir the potatoes.
Finish: Continue air frying for 10–14 minutes, until the chicken reaches an internal temperature of 165°F–175°F (74°C–79°C) and potatoes are golden and tender.
Rest & Serve: Remove chicken and let it rest for 5 minutes before serving. Garnish with fresh parsley or lemon zest if desired.