Preheat the oven to 400°F (205°C).
In a mixing bowl, combine the chicken, 2 tablespoons of the olive oil, tomato paste, smoked paprika, chopped garlic, lemon zest, chili flakes, kosher salt and black pepper; toss to coat evenly.
Heat the large oven-safe skillet over high heat and add the remaining 1 tablespoon olive oil. Sear the chicken on both sides until golden, about 3–5 minutes total.
During the last 2 minutes of searing, add the butter to the skillet to melt. Remove the chicken to a plate and set aside, reserving skillet juices.
Add the dry orzo and 2 tablespoons fresh thyme to the hot skillet and cook, stirring, until the orzo is lightly toasted, about 1 minute.
Stir in the chopped sun-dried tomatoes, chicken broth and lemon juice; season with salt and pepper. Stir in the mixed herbs (basil and remaining thyme).
Return the seared chicken and any accumulated juices to the skillet, nestling the pieces into the orzo mixture.
Bake the skillet uncovered in the preheated oven for about 15 minutes, or until the chicken is cooked through and the orzo is tender.
Serve the chicken and orzo topped with tzatziki sauce and additional basil if desired.
