Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1/2-inch cubes, then slice the chicken breast into even 1-inch strips.
In a large bowl, toss the chicken and sweet potato cubes with the olive oil, sea salt, black pepper, and garlic powder until well coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 20 to 25 minutes, or until the chicken is cooked through and the potatoes are tender.
While the base roasts, thinly slice the red onion and pit the avocado, slicing one quarter into thin wedges.
Build your bowl by placing the baby spinach at the bottom, then topping it with the warm roasted chicken and sweet potatoes.
Garnish with the red onion and avocado wedges, then finish with a bright squeeze of fresh lime juice.