Place the chicken breasts in a crock pot. Top with the cumin, paprika, chili powder, salt, lime juice, diced green chilis, and salsa. Cover and cook on high for 4-5 hours, or until chicken is tender and shreds easily. Shred the chicken lightly and replace the cover.
Heat the oil on high heat in a large saute pan. Add the peppers and onions to the pan and saute until browned in places, yet still crisp. Your pan will need to be very hot to do this. Add the cooked vegetables to the crock pot with the chicken.
Serve with tortillas, sour cream (optional), salsa, and lime wedges. Omit the tortillas and sour cream for Whole30. For Paleo use tortilla recipe linked to above.