Heat the oven: Set your oven to 425°F (220°C). Line a large sheet pan with parchment for easy cleanup.
Prep the chicken: Pat the chicken dry. If using breasts, slice into 1/2-inch strips for quick cooking.
Thighs can be left whole or cut into strips.
Season generously: In a large bowl, combine olive oil, smoked paprika, cumin, garlic powder, oregano, chili powder (if using), salt, black pepper, and lemon zest. Toss chicken to coat well.
Add the veggies: Add sliced peppers and red onion to the bowl. Toss again so the vegetables pick up the seasoning and oil.
Arrange on the sheet pan: Spread chicken and vegetables in an even layer.
Don’t overcrowd—use two pans if needed so everything roasts instead of steams.
Roast: Bake for 16–20 minutes, stirring once halfway, until the chicken is cooked through and the edges of the veggies are caramelized. Internal temp should reach 165°F (74°C).
Finish with lemon: Squeeze half the lemon over the hot chicken and vegetables. Taste and add a pinch of salt if needed.
Make the herby ranch: While the chicken roasts, whisk mayo, Greek yogurt, a splash of milk, garlic, dill, parsley, chives, lemon juice, salt, and pepper.
Adjust thickness with more milk and seasoning to taste. It should be creamy but drizzle-able.
Warm the pitas: Wrap pitas in foil and warm in the oven for the last 3–5 minutes of roasting, or char briefly over a gas flame or hot skillet.
Assemble: Layer lettuce in warm pitas, add chicken and veggies, top with cucumber, tomatoes, and feta if you like. Drizzle generously with herby ranch.
Serve: Add extra ranch and lemon wedges at the table.
A little flaky salt on top is a nice touch.