Heat olive oil in a skillet over medium heat. Cook sausage links until browned and oil begins to render, about 3 minutes. Remove from heat and let cool slightly. Remove to a small bowl.
Cut two slashes down to the bone on the skin side of each chicken thigh.
Place Artichokes in a large bowl. Add the sliced red and yellow onions and potato chunks. Add chicken thighs and sausage pieces with pan juices.
Season with kosher salt, black pepper, and Italian herbs. Drizzle with a tablespoon of olive oil.
Mix completely until all ingredients are coated in oil, 3 or 4 minutes. Transfer to large, heavy-duty roasting pan. Evenly space the chicken thighs skin side up, place potatoes on top.
Place in preheated oven until chicken is cooked through and everything is caramelized, about 1 hour. An instant-read thermometer inserted near the bone should read 165 degrees F (74 degrees C). Sprinkle with chopped fresh Italian parsley, if desired.