Preheat your oven or air fryer to 400°F (200°C). Line a baking sheet with parchment paper or lightly coat with cooking spray.
Using a sharp knife, make a deep pocket in the thickest part of each chicken breast, being careful not to cut all the way through.
In a small bowl, mix together the feta cheese, chopped roasted red peppers, spinach, olives, parsley, garlic, and basil.
Spoon equal amounts of the feta cheese mixture into each chicken pocket, about 1/3 cup, and secure the pockets using wooden toothpicks.
Season the chicken on both sides with salt and pepper, to taste.
Place the chicken on the prepared baking sheet and lightly coat with olive oil or cooking spray if using an oven. For air frying place chicken breasts into the basket. Don't overcrowd them.
Bake for 20-30 minutes, or until the internal temperature of the chicken reaches 165°F (74°C) and the chicken is fully cooked and juicy.
Drizzle the chicken evenly with lemon juice.
Serve hot, with your choice of sides, such as roasted vegetables or a salad. Enjoy!