Slice the chicken breast into thin strips and the bell peppers and onions into long slivers.
In a small bowl, combine the chili powder, cumin, garlic powder, salt, and pepper, then toss the chicken strips in the spice blend until evenly coated.
Heat a large non-stick skillet over medium-high heat and add the chicken strips, sautéing for 5-7 minutes until cooked through; add a splash of water or broth if sticking occurs.
Add the sliced peppers and onions to the skillet and cook for another 3-4 minutes until the vegetables are tender-crisp.
In a separate small pan or microwave-safe bowl, steam the cauliflower rice for 3 minutes until tender and fluffy.
Assemble the bowl by placing the cauliflower rice at the bottom, topping with the fajita chicken and vegetable mixture, and finishing with fresh salsa, lime juice, and chopped cilantro.