01 - Set the oven to 400°F and allow it to reach full temperature before assembling the packets.
02 - Cut four large sheets of heavy-duty aluminum foil, each roughly 12x16 inches, and lay them flat on a work surface.
03 - Place one chicken breast in the center of each foil sheet.
04 - Distribute the sliced bell pepper, squash, zucchini, red onion, and halved cherry tomatoes evenly around each piece of chicken.
05 - In a small bowl, whisk together the olive oil, Italian seasoning, garlic powder, paprika, salt, and black pepper until well combined.
06 - Drizzle the seasoning mixture evenly over the chicken and vegetables on each foil sheet.
07 - Fold the sides of each foil sheet up and over the chicken and vegetables, crimping the edges tightly to seal while leaving slight room for steam circulation.
08 - Transfer the sealed packets to a baking sheet and bake for 25 to 30 minutes, until the chicken is cooked through and the vegetables are tender.
09 - Carefully open each packet watching for escaping steam, then garnish with chopped fresh parsley and serve with lemon wedges alongside.