In a medium bowl, whisk together orange juice, olive oil, lemon juice, vinegar, orange zest, salt, sugar, and pepper.
Place chicken in a zip-top bag and add 3 tablespoons of the citrus dressing. Seal bag and flip a few times to make sure the chicken is fully coated. Marinate in refrigerator for 2-4 hours.
Heat grill or grill pan to medium-high heat. Take chicken out of bag and dab any excess marinade on a paper towel. If the chicken is dripping with marinade when it goes on the grill, chances are it will burn. Grill chicken 7-8 minutes on each side or until chicken reaches 165° F. Remove from grill and slice thinly on the bias.
In a large bowl, combine rice, carrots, sugar snap peas, and scallions. Add 4 tablespoons of the citrus dressing and gently toss to combine.
Serve chicken over rice and drizzle with remaining dressing, if desired.