Preheat oven to 400°F (200°C).
Cook orzo in boiling salted water according to package directions until al dente; drain and set aside.
Toss diced zucchini, bell peppers, and cherry tomatoes with half the olive oil, salt, and pepper on a baking sheet.
Roast vegetables for 15-18 minutes until tender and slightly charred.
While vegetables roast, season cubed chicken with garlic powder and remaining salt and pepper.
Heat the remaining olive oil in a skillet over medium-high heat and sear chicken until golden and cooked through.
In a large bowl, combine the cooked orzo, roasted vegetables, and seared chicken.
Whisk together lemon juice, zest, and chopped parsley, then fold into the orzo mixture before serving.