Combine ⅓ cup orange juice concentrate and soy sauce in a large resealable plastic bag. Add pork tenderloin; seal bag. Turn bag to evenly coat pork with marinade. Refrigerate for 3 to 5 hours, turning bag occasionally.

Preheat oven to 350°. Spray 2 large rimmed baking pans with nonstick spray; set aside. Cut sweet potatoes lengthwise in half; cut each half lengthwise into ¼-in.-thick slices. Place in a large bowl. Cut unpeeled mandarins into ¼-in.-thick slices; add to sweet potatoes in bowl. Add 2 Tbsp. olive oil, black pepper, garlic and salt; toss to coat. Spread evenly on one prepared baking sheet. Roast for 20 minutes or until sweet potatoes beginning to soften, turning halfway through.

Remove pork tenderloin from marinade; discard marinade. Pat tenderloin dry with paper towels. Heat 1 Tbsp. olive oil in a large nonstick skillet over medium-high heat. Add pork tenderloin to skillet. Cook for 5 to 6 minutes or until golden brown on all sides, turning frequently. Place tenderloin in baking pan with sweet potatoes and oranges. Roast for 15 to 18 minutes or until pork reaches 145° and sweet potatoes are tender. Brush pork with remaining 2 Tbsp. orange juice concentrate. Cover loosely with foil; let stand 10 minutes.

Meanwhile, cut large stalks of Broccolini in half lengthwise. Toss Broccolini with remaining 1 Tbsp. olive oil in a medium bowl. Place in the other prepared baking pan. Roast for 9 to 11 minutes or until desired doneness.

To serve, slice pork. Arrange sweet potatoes and orange slices on a large platter. Top with broccolini and sliced pork.