In a large bowl, whisk together the pineapple juice, brown sugar, ketchup, soy sauce, chicken broth, grated ginger, and minced garlic until smooth. Reserve 1 cup of marinade. Add chicken breasts to the remaining marinade and refrigerate for 30 minutes.

In another bowl, combine diced pineapple, mango, avocado, and chopped cilantro. Drizzle with lime juice and sprinkle with sea salt. Set aside.

Heat a grill pan over medium heat and brush lightly with oil. Remove chicken from marinade and grill for 6-8 minutes per side until cooked, checking doneness with a meat thermometer.

Baste the chicken occasionally with the reserved marinade while grilling.

Once cooked, let the chicken rest for a few minutes before dicing into small pieces.

Warm the mini corn tortillas. Divide diced chicken among tortillas and top with prepared salsa. Optionally add extra cilantro or lime juice and serve immediately.