Preheat oven to 425ºF.
In a large bowl, toss chicken with brown sugar, smoked paprika, garlic powder, onion powder, cayenne, salt, and olive oil.
Add lemon slices and mix again.
Spread chicken and lemons on a sheet pan in a single layer.
Roast for 15 minutes, toss, then roast 4–7 more minutes until caramelized and cooked through.
In a bowl, whisk together yogurt, dill, parsley, chives, lemon juice, olive oil, and salt.
Fold in shredded cabbage and let rest for 10–15 minutes.
Warm the pitas until soft.
Fill each pita with slaw, roasted chicken, and avocado cubes.
Serve warm and enjoy immediately!