**Preheat the oven:** Set it to 400°F (200°C)
**Prep the veggies:** Slice up the zucchini, chop the bell peppers, and cut the onion into wedges. You want everything to be roughly the same size so they cook evenly.
**Season the chicken:** Place the chicken breasts on the sheet pan. Drizzle them with 1 tablespoon of olive oil, then sprinkle with garlic powder, paprika, salt, and pepper. Rub everything in to coat the chicken well.
**Season the vegetables:** In a bowl, combine the vegetables with the remaining olive oil, garlic powder, salt, and pepper. Evenly distribute them around the chicken on the baking sheet.
**Bake:** Roast everything for about 25-30 minutes, until the chicken is cooked through (reaching 165°F internally) and the veggies are tender and slightly browned.
**Serve:** Take everything out of the oven, garnish with parsley if you like, and dig in! You’ve got a complete meal with just one pan.