Cook the pasta according to the package instructions. Once cooked, drain and set aside.
While the pasta is cooking, prepare the chicken. Cut the chicken breasts into bite-sized pieces and season with the shawarma spice blend.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken and cook until golden brown, about 6-8 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced onion and bell pepper. Cook until the vegetables are softened, about 5-7 minutes.
Add the minced garlic and cherry tomatoes to the skillet. Cook for another 2-3 minutes, until the tomatoes start to soften.
Add the cooked pasta and chicken to the skillet with the vegetables. Mix everything together and season with salt and pepper to taste.
In a separate bowl, whisk together the Greek yogurt, tahini, and lemon juice. Pour the sauce over the pasta and toss everything together until well combined.
Garnish the dish with chopped parsley and serve immediately.