Season the chicken breast evenly with sea salt, black pepper, chili powder, and cumin.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken for 5 to 6 minutes per side until fully cooked.
Transfer the chicken to a cutting board and let it rest for 3 minutes before slicing into thin strips.
In the same skillet, sauté the diced red onion and sliced bell peppers for 4 minutes until they are tender and slightly charred.
Place the cooked brown rice and shredded romaine lettuce in a serving bowl as the base.
Top the bowl with the sliced chicken, sautéed vegetables, avocado slices, and fresh salsa.
Finish by garnishing with chopped cilantro and a fresh squeeze of lime juice.