Preheat your oven to 400°F and heat a grill pan or outdoor grill over medium-high heat.
In a small bowl, whisk together the olive oil, lemon juice, minced garlic, dried oregano, sea salt, and black pepper to create the marinade.
Slice the zucchini into rounds and the red bell pepper into bite-sized strips.
Place the vegetables on a parchment-lined baking sheet and toss with half of the prepared marinade until evenly coated.
Roast the vegetables in the oven for 15-20 minutes until they are tender and show slight caramelization around the edges.
While the vegetables roast, brush the remaining marinade over the chicken breast and place it on the hot grill.
Grill the chicken for 6-7 minutes per side, or until the internal temperature reaches 165°F and the outside has beautiful char marks.
Remove the chicken from the grill and let it rest for 5 minutes to lock in the juices before slicing.
Plate the sliced chicken alongside the roasted vegetables and serve immediately.