Preheat and prep: Heat your oven to 425°F (220°C).
Line two large sheet pans with parchment for easy cleanup. Pat the chicken dry with paper towels.
Season the sweet potatoes: Toss the sweet potato cubes with 1 tablespoon olive oil, 1/2 teaspoon salt, 1/4 teaspoon pepper, and 1/2 teaspoon smoked paprika. Spread them on one sheet pan in a single layer.
Roast the sweet potatoes: Place the pan on the top rack and roast for 25–30 minutes, flipping once, until tender and lightly browned at the edges.
Season the veggies: On the second sheet pan, toss broccoli, bell pepper, and red onion with 1 tablespoon olive oil and a pinch of salt and pepper.
Set aside for now.
Mix the chicken rub: In a small bowl, combine the remaining 1 tablespoon olive oil, smoked paprika, garlic powder, onion powder, cumin, chili flakes (if using), 1 teaspoon salt, 1/4 teaspoon pepper, lemon zest, and half the lemon juice.
Coat the chicken: Rub the mixture all over the chicken breasts. Let them sit for 10 minutes while the sweet potatoes start roasting. This helps the flavors sink in.
Sear the chicken (optional but flavorful): Heat a large oven-safe skillet over medium-high.
Sear the chicken 2–3 minutes per side until golden. Transfer the skillet to the oven to finish, or move the chicken to the veggie sheet pan.
Roast chicken and veggies: Slide the chicken and veggie pan into the oven on the lower rack. Roast for 15–18 minutes, until the chicken reaches an internal temperature of 165°F (74°C) and the veggies are crisp-tender.
If needed, remove the chicken first and give the veggies a few extra minutes.
Make the sauce: Stir together Greek yogurt, grated garlic, remaining lemon juice, olive oil, and a pinch of salt and pepper. Thin with a splash of water if you like it drizzly. Taste and adjust salt or lemon.
Rest and slice: Let the chicken rest 5–10 minutes, then slice across the grain.
Toss the roasted sweet potatoes with chopped herbs for a fresh finish.
Assemble the bowls: Divide spinach or kale among 4 meal prep containers. Top with equal portions of sweet potatoes, roasted veggies, and sliced chicken. Add optional cooked grains if you want extra carbs and fiber.
Finish: Spoon the yogurt sauce into small lidded cups to keep it separate, or drizzle over the bowls just before eating.
Sprinkle with more herbs if you like.