2 cups refrigerated prepared mashed potatoes
1/2 tsp. kosher salt
Cooking spray
1 1/2 pounds skinless, boneless chicken thighs
1/4 tsp. garlic powder
1/4 tsp. onion powder
1/2 tsp. dry mustard
1/2 tsp. black pepper
1 tbsp. apple cider vinegar
2 1/2 tbsp. light brown sugar
1 cup unsalted ketchup