Peel and dice the sweet potato into uniform half-inch cubes, then soak them in a bowl of cold water for 10 minutes to remove excess starch.
While the potatoes soak, cut the chicken breast into bite-sized pieces and season thoroughly with sea salt, black pepper, garlic powder, and smoked paprika.
Drain the sweet potatoes and pat them completely dry with a clean kitchen towel to ensure they crisp up in the pan.
Heat the avocado oil in a large cast-iron or non-stick skillet over medium-high heat.
Add the diced sweet potatoes to the skillet in a single layer and cook for 8-10 minutes, stirring occasionally, until they are tender and caramelized on the edges.
Add the diced chicken and red bell peppers to the skillet, sautéing for another 5-7 minutes until the chicken is cooked through and no longer pink.
Add the fresh spinach to the pan and toss for 30-60 seconds until just wilted, then remove from heat and serve immediately.