Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Rinse the farro under cold water in a fine-mesh sieve, then place it in a small saucepan with 1 cup of water; bring to a boil, reduce heat to low, cover, and simmer for 20-25 minutes until tender.
While the farro cooks, cut the chicken breast into 1-inch bite-sized cubes and chop the broccoli, red bell pepper, and red onion into similar sizes.
Place the chicken and vegetables on the prepared baking sheet, drizzle with olive oil, and sprinkle with sea salt, black pepper, garlic powder, and dried oregano.
Toss the mixture thoroughly to ensure everything is evenly coated, then spread it out in a single layer.
Roast in the oven for 18-20 minutes, or until the chicken is cooked through and the vegetables have developed slightly charred, crisp edges.
Drain any excess water from the cooked farro and fluff it with a fork.
In a large serving bowl, combine the cooked farro with the roasted chicken and vegetables, then drizzle with fresh lemon juice and toss once more before serving.