Preheat your oven to 425°F (220°C). Toss the diced sweet potatoes with olive oil, salt, and pepper on a baking sheet. Spread them out in a single layer and roast for 25-30 minutes, or until tender and slightly caramelized, stirring halfway through.
While the sweet potatoes are roasting, season the chicken breasts with salt and pepper. In a skillet over medium heat, cook the chicken for 6-7 minutes on each side or until fully cooked (internal temperature should reach 165°F). Remove from heat and let it rest for a few minutes.
Once the chicken has rested, shred it using two forks and mix it with the BBQ sauce until well coated.
In a large bowl, combine the roasted sweet potatoes, corn, black beans, and BBQ chicken. Toss gently to mix.
Serve the mixture in bowls, topped with diced avocado, chopped cilantro, and a squeeze of lime juice.