Boil chickpea pasta in salted water according to package directions until al dente.
Drain pasta and rinse immediately with cold water to stop the cooking process and remove excess starch.
In a large mixing bowl, whisk together the Greek yogurt, Dijon mustard, lemon juice, garlic powder, salt, and black pepper until smooth.
Add the cooled pasta, diced chicken breast, bell pepper, cucumber, and red onion to the mixing bowl.
Toss all ingredients together until the pasta and vegetables are evenly coated with the yogurt dressing.
Fold in the chopped fresh parsley.
Cover and refrigerate for at least 30 minutes before serving to allow the flavors to meld and the dressing to set.