Preheat oven to 425°F (220°C), preferably using convection mode.
In a large bowl, toss chicken with brown sugar, spices, salt, and olive oil. Add lemon slices and mix well.
Spread chicken evenly on a sheet pan without overcrowding.
Bake for 15 minutes, toss, then bake another 4–7 minutes until caramelized and cooked through.
In a separate bowl, mix yogurt, herbs, lemon juice, olive oil, and salt.
Add cabbage and toss well. Let sit 10–15 minutes to soften.
Warm pitas, then fill with slaw, Sheet Pan Chicken Pitas filling, and avocado. Serve immediately.