Cut chicken into one-inch chunks and season with chili powder, sea salt, and black pepper. Heat a couple of tablespoons of oil in a large skillet over medium high flame. Add chicken and sauté until golden brown and cooked through (about 6 minutes). Remove chicken from pan.
While chicken cooks, prepare vegetables: trim ends of brussels sprouts and cut in half, chop onion, kale, and dice garlic.
Add another tablespoon of oil to pan then add in garlic and onion. Allow them to cook down until onions start to become translucent and garlic is fragrant (about 2 minutes).
Add in brussels sprouts, and kale. Season with more sea salt and black pepper. Cook for about 3 minutes or until sprouts start to brown a bit and kale wilts then stir in maple syrup. Cook for another 2 to 3 minutes.
Mix in sweet potato noodles then turn off heat. Add chicken back to pan and allow residual heat and steam to soften sweet potato noodles.
If desired, sprinkle walnut pieces over top for added texture. Serve warm.