Preheat your oven to 425°F (220°C). Line a sheet pan with parchment paper or a light coating of oil to prevent sticking.
In a small bowl, whisk together the balsamic vinegar, honey, minced garlic, thyme, salt, and pepper. This will be your glaze that flavors both the chicken and the potatoes.
Spread the sweet potato chunks on the sheet pan in a single layer. Drizzle with 1 tablespoon of olive oil and toss to coat. This helps them caramelize nicely.
Pat the chicken thighs dry with paper towels (this helps them get a good sear). Place them on the sheet pan, nestled among the sweet potatoes.
Pour the balsamic glaze over the chicken and potatoes, turning the chicken a few times to coat. If you like, add the cherry tomatoes at this stage for a pop of color and a touch of sweetness.
Roast in the preheated oven for 20–25 minutes, then rotate the pan and spoon some of the pan juices over the chicken and potatoes. Return to the oven for another 5–10 minutes, until the chicken reaches an internal temperature of 165°F (74°C) and the potatoes are tender.
If you’d like a little extra glaze at the end, remove the pan from the oven, baste with any remaining glaze, and let it rest for a couple of minutes before serving.
Garnish with chopped parsley for a fresh, bright finish. Serve warm, with any pan juices spooned over the chicken and potatoes.