In a small bowl, mix together the chili powder, ground cumin, paprika, dried oregano, salt, and black pepper to make the fajita seasoning.
Place the sliced chicken breasts, bell peppers, onion, and minced garlic in the crockpot.
Drizzle the olive oil over the chicken and vegetables, then sprinkle the fajita seasoning evenly over everything. Toss everything together until the chicken and vegetables are evenly coated with the seasoning.
Squeeze the lime juice over the mixture in the crockpot.
Cover the crockpot and cook on low for 4-6 hours or on high for 2-3 hours, or until the chicken is cooked through and the vegetables are tender.
Once cooked, use a fork to shred the chicken directly in the crockpot and mix it with the vegetables and juices.
Serve the chicken fajita mixture warm in tortillas, and let everyone customize their fajitas with their favorite toppings such as shredded cheese, sour cream, salsa, guacamole, cilantro, and lime wedges.
Enjoy your delicious and flavorful Crockpot Chicken Fajitas!