Heat the oven to 425°F. Whisk Dijon, maple syrup, olive oil, vinegar, and garlic powder.
Toss carrots and Brussels sprouts with oil, salt, and pepper on a sheet pan. Roast briefly to give the vegetables a head start.
Season pork with salt and pepper, then brush all over with the maple-Dijon mixture. Add it to the pan with the vegetables.
Roast until the pork is cooked through and the vegetables are tender and caramelized. Rest the pork before slicing.
Slice and serve with the roasted vegetables and any juices from the pan.