Roast the potatoes: Preheat your oven to 400°F (200°C). Wash and scrub the potatoes, then cut them into bite-sized pieces. Toss the potatoes with olive oil and spread them on a baking sheet. Roast for 25-30 minutes, or until tender and golden brown.
Cook the chicken: In your crock pot, combine the chicken breasts, water or broth (enough to cover the chicken), and taco seasoning packet. Cook on low for 4-6 hours, or on high for 2-3 hours, or until the chicken is fully cooked through. Shred the chicken with two forks.
Sauté the vegetables: While the chicken cooks, heat a pan with a drizzle of oil over medium heat. Slice the bell pepper and onion. Sauté them in the pan until softened and slightly browned, about 5-7 minutes.
Assemble: Once the potatoes are roasted and the chicken is shredded, take out the potato pan. Top each potato with shredded chicken, sauteed vegetables, and your desired amount of enchilada sauce or salsa.
Bake and serve: Preheat your oven to broil. If using cheese, sprinkle it over the loaded potatoes. Broil for 2-3 minutes, or until the cheese is melted and bubbly. Serve immediately while hot.