Place a large baking sheet into the oven, and preheat the oven to 425 degrees. Make sure to leave the pan in the oven while it preheats!
In a small mixing bowl, add mustard, pure maple syrup, thyme leaves, sea salt, and freshly cracked pepper, to taste. Whisk well to combine.
Place the butternut squash, baby potatoes, and shallots in a mixing bowl; drizzle with some olive oil and season with sea salt and freshly cracked pepper, to taste. Toss to coat evenly.
Season the chicken thighs well with sea salt and freshly cracked pepper, to taste. Spoon a little bit of maple mustard sauce over each piece of chicken then brush the sauce to coat each piece. Reserve the remaining for later.
Carefully remove the pan from the oven (remember, it's very HOT), and add chicken thighs, skin side down, to the pan.
Spread the baby potatoes, butternut squash, and shallots in an even layer around the chicken thighs, careful not to overcrowd the pan, or they won't roast well.
Place the hot baking sheet into the hot oven and bake for 18-20 minutes.
Meanwhile, place the green beans in the same bowl that you used for the other veggies.
Drizzle with some olive oil then season well with sea salt, freshly cracked pepper, to taste. Toss to coat evenly.
After 18-20 minutes, flip the chicken over then add the green beans to the baking sheet.
Return to oven for another 10-15 minutes, until chicken is cooked through and at an internal temperature of 165 degrees.
Remove from the oven and brush chicken with reserved maple mustard sauce.