Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Trim the ends of the green beans and spread them onto the baking sheet, tossing with 0.5 tbsp of olive oil, half of the sea salt, and half of the black pepper.
Roast the green beans for 15 to 18 minutes, shaking the pan halfway through, until they are tender and slightly blistered.
While the beans are roasting, pat the chicken breast dry and season both sides with dried oregano, garlic powder, lemon zest, and the remaining sea salt and black 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 to 8 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Remove the skillet from the heat and immediately drizzle the fresh lemon juice over the chicken to create a light pan sauce.
Serve the chicken alongside the roasted green beans, pouring any extra lemon-herb juices from the pan over the meat.