Chicken Salad with Melon, Feta & Greens

Heat the oven to 350°F.  Place the walnuts onto a rimmed baking sheet.  Bake for 8 minutes or until the walnuts are lightly browned.  Remove the walnuts to a cutting board and let cool for 10 minutes. Coarsely chop the walnuts.Heat the lemon juice and 1/4 cup mint in a 1-quart saucepan over medium-high heat for 1 minute or until the mint is wilted.  Remove the saucepan from the heat.  Let stand for 10 minutes.  Strain the mint mixture into a small bowl.  Add the olive oil, vinegar and sugar and beat with a fork or whisk.  Season the dressing with the black pepper.Season the chicken with additional black pepper.  Heat 1 tablespoon vegetable oil in a 12-inch skillet over medium-high heat.  Add the chicken in batches and cook for 15 minutes or until it's well browned on both sides and cooked through, adding more oil as needed during cooking.  Remove the chicken to a cutting board.  Cut the chicken into thin slices.Place the chicken, cantaloupe, feta and 2 tablespoons mint into a large bowl.  Add half the dressing and toss to coat.Place the watercress and remaining mint into a large bowl.  Add the remaining dressing and toss to coat.  Divide the watercress mixture among 6 plates.  Top with the chicken mixture.