Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Cut the broccoli, red bell pepper, and yellow squash into uniform, bite-sized pieces to ensure even cooking.
Place the chopped vegetables on the prepared baking sheet and drizzle with the extra virgin olive oil.
Sprinkle the garlic powder, dried oregano, sea salt, and black pepper over the vegetables and toss thoroughly to coat.
Spread the vegetables out into a single layer, ensuring they are not overcrowded so they roast rather than steam.
Roast in the oven for 15-20 minutes, or until the vegetables are tender-crisp and show slight charred edges.
While the vegetables roast, remove the skin from the rotisserie chicken and slice or shred the breast meat into 5-ounce portions.
Remove the vegetables from the oven and immediately drizzle with fresh lemon juice to brighten the flavors.
Plate the warm rotisserie chicken alongside the roasted vegetable medley and serve immediately.