Heat olive oil in a 12-inch heavy-bottomed skillet over medium-high heat until shimmering.
Season chicken cubes with salt and pepper and add to the skillet, searing until browned on all sides, approximately 5 minutes.
Remove chicken from skillet and set aside on a clean plate.
Add sweet potato and onion to the residual fat in the skillet; sauté for 5 minutes until onion is translucent and sweet potato edges begin to soften.
Add garlic, rice, thyme, and rosemary; cook for 2 minutes while stirring constantly to toast the rice grains.
Deglaze the skillet with chicken broth, scraping the bottom with a wooden spoon to incorporate any browned bits (fond).
Return chicken and any accumulated juices to the skillet and bring the liquid to a boil.
Cover with a tight-fitting lid, reduce heat to low, and simmer for 15 minutes or until rice is tender and liquid is fully absorbed.
Remove from heat; stir in the diced apple and kale.
Cover and allow to rest for 5 minutes to wilt the kale and slightly soften the apple via residual heat.
Fluff the mixture with a fork and serve immediately.