While you preheat your oven to 425 degrees Fahrenheit, begin melting the butter in a pan over a medium heat. Then, whisk in the spicy mustard, honey, cayenne pepper, red chili flakes, hot sauce, and garlic powder until everything is well combined. Bring this mix to a boil and then turn down the heat and let it simmer for another 5 minutes or so.
Season your chicken with salt and pepper, and then coat each piece with the sauce and lay them all in a single layer on a baking sheet. Bake them for 15 minutes on each side, and feel free to add more sauce when you take them out to flip them over. Serve warm and enjoy!