Cut meat into thin strips and set aside. In a small bowl, combine orange juice, agave, soy sauce, cornstarch and ginger; mix well. Heat 1 tablespoon oil in a wok or large skillet over medium heat. Add carrots and celery; stir-fry about 3 minutes. Remove vegetables and set aside. Pour remaining oil into skillet. Add chicken; stir-fry about 3 minutes. Return vegetables to skillet; add sauce mixture and nuts. Cook and stir over medium-high heat until thickened. Serve over hot rice.