Preheat oven to 400°F. Arrange taco shells in a 9x13" baking dish (you can ball up foil to arrange to help the taco shells stand up if your shells keep falling over).
Heat cooked chicken, salsa, chili powder, cumin, garlic powder, onion powder, and 1 teaspoon of the lime juice in a large skillet over medium-high heat. Cook 4-5 minutes, until the spices are fragrant and excess moisture has evaporated (you want the chicken to be moist and flavorful, but not too wet so the shells won't get soggy).
Fill the taco shells. Place 1 tablespoon of black beans (that have been drained, rinsed, and patted dry) in the bottom of each taco shell. Then divide chicken between the taco shells, and finally top each taco with one tablespoon of shredded cheese.
Bake for five minutes, until cheese has melted.
While tacos are baking, shred lettuce (if not already shredded) and combine chopped tomatoes, remaining lime juice, cilantro and salt for the "cheater pico".
Let cool a couple minutes before serving, until tacos are easily handled. Top with lettuce and cheater pico and enjoy!
Nutrition information includes lettuce and cheater pico. Information will also vary based on exact ingredients you use (i.e. different parts of the chicken, different cheeses, etc.).