1 lemon, thinly sliced
2 (8 ounce) skinless, boneless chicken breast halves, halved crosswise
1 20-ounce package refrigerated diced sweet potatoes, such as Simply Potatoes®
½ tsp. freshly ground black pepper
½ tsp. snipped fresh rosemary
¾ tsp. kosher salt
3 cloves garlic, minced
4 tsp. canola or olive oil