Preheat the oven to 425°F (220°C).
In a bowl, combine olive oil, cumin, coriander, paprika, turmeric, cinnamon, cayenne pepper, salt, and pepper.
Coat the chicken thighs in the spice mixture and place them on a baking sheet.
Roast the chicken in the oven for 25-30 minutes or until fully cooked.
Let the chicken rest for 5 minutes, then slice thinly.
Warm the pita bread and layer with tzatziki sauce, lettuce, tomatoes, onions, and sliced chicken.
Serve immediately and enjoy!