**Preheat the Grill or Oven:** Preheat your grill to medium-high heat (about 400°F) or your oven to 375°F.
**Prepare the Sauce:** In a small bowl, whisk together the soy sauce, honey, brown sugar, rice vinegar, sesame oil, garlic, and ginger. Heat the mixture in a small saucepan over medium heat. Stir in the cornstarch slurry and cook until the sauce thickens. Set aside.
**Assemble the Foil Packets:** Cut 4 large sheets of aluminum foil. Place one chicken breast in the center of each sheet. Divide the pineapple chunks, bell peppers, red onion, and zucchini evenly among the packets. Drizzle with olive oil and season with salt and pepper.
**Add the Sauce:** Spoon the teriyaki sauce over each chicken breast and the vegetables.
**Seal the Packets:** Fold the sides of the foil over the chicken and vegetables, sealing the packets tightly to trap the steam.
**Cook the Packets:**
- **On the Grill:** Place the foil packets on the grill and cook for 20-25 minutes, flipping halfway through.
- **In the Oven:** Place the packets on a baking sheet and bake for 25-30 minutes.
**Serve:** Carefully open the foil packets to release the steam. Serve the chicken and vegetables directly from the foil or transfer to plates.