Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Dice the zucchini, red bell pepper, and red onion into uniform 1-inch pieces to ensure even roasting.
Place the vegetables on the baking sheet, drizzle with half of the olive oil, and sprinkle with half of the salt, pepper, and oregano.
Roast the vegetables for 20 minutes until they are tender and slightly charred at the edges.
While the vegetables roast, cut the chicken breast into bite-sized cubes and mince the garlic.
Heat the remaining olive oil in a skillet over medium-high heat.
Add the chicken to the skillet and cook for 5-7 minutes until golden brown and cooked through.
Stir in the minced garlic and remaining spices during the last minute of cooking until fragrant.
Toss the roasted vegetables into the skillet with the chicken, drizzle with fresh lemon juice, and serve immediately.