In a large bowl, combine the chicken thighs with the jerk seasoning, olive oil, garlic powder, onion powder, salt, and black pepper. Toss to coat the chicken evenly. Cover and marinate in the refrigerator for at least 30 minutes, or up to 2 hours for deeper flavor.
Preheat your grill or a grill pan over medium-high heat.
Remove the chicken from the marinade and grill for 6-7 minutes on each side, or until the chicken is cooked through and has nice grill marks. Use a meat thermometer to check that the internal temperature reaches 165°F (75°C).
Once cooked, transfer the chicken to a cutting board and let it rest for a few minutes before slicing it into strips.
In a dry skillet over medium heat, warm the corn tortillas for about 30 seconds on each side until they are pliable.
To assemble the tacos, layer slices of jerk chicken on each tortilla. Top with diced mango, sliced red onion, and bell pepper.
Finish with avocado slices and a sprinkle of fresh cilantro. Serve with lime wedges on the side for an extra zing.