Cut off the rind and excess fat around the pork chops. Mix the chili powder, paprika, and some salt and pepper with the olive oil in a wide baking dish. Add the thyme, garlic, star anise, and coriander seeds. Add the pork chops and turn to coat. Cover and let marinate for at least 30 minutes, or in the refrigerator overnight.
Heat the oven to 350°F. Bake the pork chops, uncovered, for about 15 minutes until the meat is just firm when lightly pressed.
Meanwhile, bring a pan of salted water to a boil. Peel the sweet potatoes and cut into 5/8- inch slices. Add to the pan and cook for 7 to 8 minutes until almost tender when pierced with a skewer. (They should be slightly undercooked at this stage.) Drain and refresh under cold running water. Dice the potatoes; set aside.