Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Trim the ends off the Brussels sprouts and halve them, slice the carrots into thin rounds, and chop the red bell pepper into bite-sized pieces.
Place the vegetables on the baking sheet and toss with 0.5 tbsp of olive oil, 0.25 tsp of sea salt, and 0.125 tsp of black pepper.
Roast the vegetables for 20-25 minutes, tossing halfway through, until they are tender and show golden-brown edges.
While the vegetables roast, season both sides of the chicken breast with garlic powder, dried oregano, and the remaining salt and pepper.
Heat the remaining 1 tbsp of olive oil in a heavy-bottomed skillet over medium-high heat.
Place the chicken in the skillet and sear for 6-7 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden.
Remove the chicken from the pan and let it rest for 5 minutes before slicing it against the grain.
Plate the sliced chicken alongside the roasted vegetables and serve immediately.