Peel and chop the sweet potato into 1-inch cubes. Toss with 1 tablespoon coconut oil and 1 teaspoon of Italian seasoning and place on a lined baking sheet. Bake for until fork tender (20-25 minutes).
In a pan over medium-high heat, melt 1 tablespoon coconut oil. Add the diced onion to the pan and cook until translucent. Stir in the minced garlic and cook and additional 1-2 minutes. Toss in the cubed chicken and cook until no longer pink (10 minutes), stirring occasionally.
Remove the stem of the head of broccoli, keeping only the florets. Trim and halve the brussels sprouts. Toss the broccoli and brussels sprouts into the chicken, and cook an additional 1-2 minutes. Remove the pan from heat.
To prepare the sauce, add the roasted sweet potatoes, coconut milk and remaining 1 tablespoon Italian seasoning to a high speed blender or food processor and puree until smooth. Add salt, to taste.
Scoop the chicken mixture into a well-greased 8×11 glass baking dish, leaving any liquid in the pan. Pour the sweet potato sauce evenly over the chicken. Bake for 30 minutes.