Preheat oven to 425°F. Line a large baking sheet with parchment paper.
In a small bowl, combine olive oil and blackened seasoning.
Add tomatoes, jalapeño, and red onion to the baking sheet. Drizzle with half of the oil mixture and toss to coat.
Brush the chicken evenly with the remaining oil mixture.
Nestle the chicken among the vegetables in a single layer.
Bake for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are roasted.
Season with salt to taste. Serve with lime wedges.