How to Make It
Whisk together orange juice, 1/2 cup balsamic vinegar, and maple syrup in a bowl. Set aside.
Heat 1 tablespoon oil in a large skillet over medium-high. Season chicken with 1/2 teaspoon salt and 1/2 teaspoon pepper. Add to skillet; cook until browned, about 5 minutes. Turn chicken over; pour balsamic mixture into skillet. Cook, turning chicken every few minutes, until a thermometer inserted in the thickest portion registers 165°F, about 12 minutes.
While chicken cooks, heat a grill pan over high. Drizzle 1 tablespoon oil over radicchio. Place on hot grill pan; cook until charred on all sides, turning occasionally, about 3 minutes. Transfer to a cutting board; let cool 3 minutes. Place oranges on grill pan; cook until charred, about 3 minutes. Transfer to a platter. Roughly chop radicchio; add to oranges. Add cheese, walnuts, remaining 1 tablespoon oil, remaining 1/2 teaspoon salt, and remaining 1/2 teaspoon pepper; toss to coat.
Remove cooked chicken from balsamic mixture in skillet; arrange on salad. Continue cooking balsamic mixture, stirring often, until reduced to 1/4 cup. Whisk in remaining 1/4 cup balsamic vinegar. Remove from heat; whisk in butter. Drizzle over chicken and salad.