Preheat oven to 400°F (200°C). Toss cubed sweet potatoes with 1 tablespoon olive oil, salt, pepper, and half the fresh thyme. Spread on a baking sheet and roast for 25-30 minutes until tender and caramelized.
In a small bowl, whisk together maple syrup, Dijon mustard, minced garlic, and a pinch of salt and pepper to create the maple Dijon glaze.
Heat remaining olive oil in a skillet over medium-high heat. Season chicken breasts with salt, pepper, and remaining thyme.
Pan-sear chicken breasts for 3-4 minutes on each side until golden brown.
Brush chicken generously with the maple Dijon glaze, then transfer skillet to the oven and roast for 10-12 minutes until cooked through and glaze is caramelized.
In the last 2 minutes of roasting, add baby spinach to the skillet to wilt gently with the chicken.
Remove chicken and spinach from oven. Slice chicken breasts.
Assemble bowls by layering roasted sweet potatoes and wilted spinach as a base. Arrange sliced chicken on top and drizzle with any remaining glaze from the skillet.