In a medium saucepan, bring 6 cups of water (or low FODMAP chicken broth) to boil, then add chicken breasts and turn temperature to medium and cook for 15-18 minutes depending on how large the chicken breasts are. When chicken is done, remove from water and chop into bite size pieces.
Meanwhile, steam chopped green beans in a steamer over boiling water until al dente, then set aside to dry and cool.
In a small bowl, combine dressing ingredients.
To segment orange: cut away the skin; cut between the membranes to release sections; if your sections are large, cut in half crosswise.
In a large bowl, combine dressing, chopped chicken, green beans, celery, and slivered almonds. Gently toss in the orange sections.
Serve chicken on a bed of mixed leafy greens.