Place prepared bell peppers and onions in the bottom of a slow cooker. Add half of the diced tomatoes and sprinkle the garlic salt evenly over the top.
Lay the chicken over the top of the peppers and onions and sprinkle with taco seasoning and chili powder. Add the remaining diced tomatoes and place the lid on the slow cooker.
Once cooked, remove chicken from the slow cooker and place onto a cutting board. Slice into 1" strips, place into a separate bowl and squeeze the juice of ½ lime over the chicken to season.