If you are making your own shredded chicken, place the chicken breasts in your slow cooker. In a small bowl, whisk together the bbq sauce, worcestershire sauce, vinegar and salt and pepper. Pour sauce mixture over chicken. Cook on high for 3-4 hours. Once chicken is cooked through, remove the breasts and shred into pieces (I usually use a stand mixer for this, just beat the chicken with the paddle attachment OR you can use a fork as well.). Return chicken to slow-cooker and toss with bbq sauce mixture.Heat oven to 350°. Spray one large baking sheet with nonstick spray to coat.Arrange one bag of the chips on the prepared sheet and top with half of the bbq shredded chicken, black beans, onions, jalapeños and cheese. Top with another layer of chips and repeat the toppings.Bake the nachos until the cheese is melted, about 20-25 minutes. Sprinkle with fresh cilantro and your choice of toppings (avocado, pico de gallo, salsa, sour cream). Serve immediately.