Line a sheet tray with parchment paper and preheat the oven to 425°
In a large bowl, toss the tomatoes and asparagus with 2 tablespoons of coconut oil. Add half the salt, half the pepper, and half the onion powder. Spread out evenly on the sheet tray. Place the sliced lemon on top of the veggies.
In the same large bowl add the chicken and toss with the remaining 2 tablespoons coconut oil, remaining salt, pepper, and garlic powder. Lay it on top of the veggies and lemon.
Bake for 20-23 minutes, until the chicken is cooked through and the veggies are tender.