Place the chopped sweet potato in a microwave-safe dish with 1/4 cup water, cover, and microwave 4 minutes until slightly tender; drain and set aside.
In a small bowl, whisk together the citrus mix: soy sauce, orange juice, and lime juice; set aside.
In another small bowl, combine the Cajun spice mix: smoked paprika, garlic powder, onion powder, salt, brown sugar, dried oregano, dried thyme, black pepper, and cayenne (if using). Remove 1 tablespoon of this mix and reserve for the potatoes and beans.
Pat the chicken dry and toss with the remaining Cajun spice mix until evenly coated.
Heat 1 tablespoon olive oil in a large skillet over high heat. Add the chicken in an even layer and sear undisturbed 1–2 minutes, flip and sear another 1–2 minutes. Add 2 tablespoons of the citrus mix, reduce heat to medium-high, and continue cooking, stirring, until chicken is cooked through, about 2 more minutes. Transfer chicken to a plate and tent with foil to keep warm.
Wipe out the skillet, add the remaining 1 tablespoon olive oil and 1 tablespoon citrus mix, then add the microwaved sweet potatoes, chopped bell peppers, and the reserved 1 tablespoon Cajun spice mix. Stir to combine, press into a single layer, and cook over medium-high until potatoes begin to char about 2 minutes, then continue cooking 1–2 minutes more until fork-tender. Transfer to a plate and keep warm.
Add the black beans, drained fire-roasted tomatoes, any remaining citrus mix, and remaining Cajun mix to the skillet over medium-high heat; cook about 2 minutes until warmed through.
Divide the beans and tomatoes, chicken, and potatoes/peppers among 4 bowls. Top with avocado, chopped pineapple, and garnish with fresh parsley before serving.
