1 tsp. Freshly ground black pepper, divided
1 1/2 tsp. Kosher salt, divided
1 tbsp. Olive oil
2 tbsp. Unsalted butter, melted
8 oz. Brussels sprouts, trimmed and halved
1/2 Acorn squash, seeded and cut crosswise into slices
3 Large shallots, peeled and quartered
4 cups Cubed peeled butternut squash
4 Bone-in, skin-on chicken breasts
1 tbsp. Pure maple syrup
1 tbsp. Dijon mustard
1 tbsp. Chopped fresh sage, divided