Pierce the potatoes in a few places with a fork; place on a microwave-safe plate and microwave until tender, turning once, about 15 minutes. Set aside.
Meanwhile, melt 1 tablespoon butter in a large skillet over medium heat. Add the onion, carrot and celery and cook, stirring occasionally, until the vegetables are tender, about 7 minutes. Add the turkey and 1/4 teaspoon each salt and pepper; cook, breaking up the meat with a wooden spoon, until no longer pink on the surface, about 5 minutes. Stir in the ketchup, chili sauce, 1/2 cup water, the chili powder and garlic powder; continue cooking until the meat is cooked through, 3 to 5 more minutes.
Split the baked potatoes open lengthwise, dot with the remaining 1 tablespoon butter and gently fluff the flesh with a fork. Top with the turkey mixture and sprinkle with the cheese while still hot.