Blend the chicken stock, herbes de Provence, garlic, and salt in a large bowl. Add in the chicken and refrigerate for a minimum of 12 hours.
Preheat oven to 450 degrees. Drain chicken and place on wire rack on a baking sheet. Roast in oven for 40-50 minutes, or until internal temperature reaches 158 degrees. Cool chicken until warm enough to handle. Pull/cut large bite sized pieces of chicken and place in bowl. Toss with vinaigrette before serving.
Mustard Herb Vinaigrette
Place all of the ingredients (minus the oil and salt) in a blender and puree. Slowly drizzle in the olive oil until vinaigrette becomes emulsified. Season with salt.
Toss potatoes with a little oil and season with salt. Place on baking sheet and roast for 15-20 minutes, or until soft on the inside and browning on the outside.
Toss the green beans with a little oil and season with salt. Place on baking sheet and roast for 10-15 minutes, or until they start to brown.
Toss the vegetables, arugula, shallots, and a little vinaigrette in a bowl. Serve with chicken on top.