Chicken in Easy Green Pumpkin Seed Sauce

Name: Chicken in Easy Green Pumpkin Seed Sauce
Ingredients: 6(about 3 ¾ pounds total) bone-in, skin-on chicken breast halves; 1small white onion, sliced; 4 garlic cloves, peeled and halved; 1/2teaspoon EACH dried marjoram and thyme; 3 bay leaves; Salt; 1 1/4cups (about 6 ounces) hulled untoasted pumpkin seeds (pepitas); 8ounces (5 to 6 medium) tomatillos, husked, rinsed and roughly chopped; 2large romaine lettuce leaves, torn into large pieces; Fresh hot green chile to taste taste (roughly 2 serranos or 1 jalapeño), stemmed and roughly chopped; The leaves from a small sprig of fresh epazote, plus an additional sprig for garnish; 1/2cup loosely packed chopped cilantro, plus a few sprigs for garnish; 1 1/2tablespoons vegetable oil or olive oil; 2 medium (about 12 ounces total) chayotes, peeled if you wish, pitted and cut into ½-inch cubes; 2medium (10 ounces total) zucchini, cut into ½-inch cubes