6 cups cubed peeled butternut squash (about 3 pounds)
3 medium carrots, peeled and cut into 1/2-inch pieces (about 1 cup)
2 parsnips, peeled and cut into 1/2-inch pieces (about 2 1/2 cups)
2 small red onions, cut into 1-inch wedges
1 medium sweet potato, peeled and cut into 1/2-inch pieces (about 2 cups)
1/4 cup extra-virgin olive oil, divided
1 tablespoon minced fresh rosemary
3/4 teaspoon kosher salt, divided
3/4 teaspoon pepper, divided
4 (6-ounce) skinless, boneless chicken breast halves
1/2 cup unsalted chicken stock
1/4 cup dry white wine
2 tablespoons whole-grain mustard
2 teaspoons honey