Preheat oven to 400 degrees F.
Place a rimmed baking sheet in the oven while it heats so it will be nice and hot.
In a large bowl, toss 1 Tbsp of oil with the bell peppers and onions. Carefully remove the pan from the oven and evenly spread onions and peppers across the pan. Place in the oven and bake for 8 minutes.
Mix all of the seasonings together in a small bowl. In the same bowl you mixed vegetables in, mix chicken, homemade fajita seasoning, and the remaining oil together.
Remove vegetables from oven and carefully add the seasoned chicken to the pan. Be sure to separate them so that they don't bake/stick together.
Return the pan to the oven and bake another 15-20 minutes, or until the vegetables are roasted and the chicken is golden brown.
Remove from oven, squeeze lime juice over the top, and serve with desired toppings.