Chicken breast, new potatoes, and sugar snap peas are all steamed in the same basket along with fresh oregano for this satisfying dinner salad. A lively lemon-Dijon dressing, salty feta, and of course Niçoise olives give it a lift.
Set a steamer basket in a wide pot containing 1 inch water; bring to a boil. Season chicken with salt. Lay oregano sprigs in bottom of basket; add chicken and potatoes. Reduce heat to medium, cover, and steam until potatoes are fork-tender, 12 to 14 minutes. Transfer potatoes to a plate; add peas to basket. Cover and cook until peas are tender and chicken is cooked through, 2 to 3 minutes more. Transfer chicken to plate; run peas under cold water in a colander. Shred chicken into bite-size pieces.
Whisk together lemon juice, Dijon, 1/2 teaspoon water, and oil. Stir in chopped oregano; season with salt and pepper. Toss lettuces, potatoes, chicken, and peas lightly with dressing. Arrange on plates with cheese and olives. Drizzle with additional dressing and serve.