Start by patting your chicken dry with paper towels. This helps it sear better. Season both sides with salt, cracked black pepper, paprika, and onion powder if using. Next, toss the sweet potato cubes with 1 tablespoon olive oil, a pinch of salt, and pepper in a bowl until evenly coated.
Heat 1 tablespoon of olive oil in your skillet over medium heat. Once hot, place the chicken thighs skin-side (or top-side) down. Sear for about 3 to 4 minutes per side, until golden brown. You're not cooking it through yet—just building flavor and sealing in juices. Remove the chicken and set it aside on a plate.
In the same skillet, add the remaining tablespoon of olive oil. Toss in the cubed sweet potatoes and let them cook, stirring occasionally, for 6 to 8 minutes. You want them to soften slightly and start developing a bit of golden color.
Once the sweet potatoes begin to soften, stir in the minced garlic and sauté for another minute to release its aroma. Carefully nestle the seared chicken back into the skillet with the sweet potatoes. Add sprigs of rosemary on top. Cover the skillet and cook over medium-low heat for 10 to 15 minutes until the chicken is fully cooked and the potatoes are fork-tender.
Once everything is cooked through, remove the lid and turn off the heat. Discard the rosemary sprigs if desired. Squeeze fresh lemon juice over the skillet for brightness and sprinkle with chopped thyme or parsley for added color and flavor. Serve hot right from the skillet for a cozy, delicious meal.