Pat the chicken breasts dry and generously season both sides with salt and black pepper.
Heat a skillet over medium-high heat and spray with cooking spray or add a thin drizzle of oil so the pan is lightly coated.
When the skillet is hot, add the chicken breasts and cook undisturbed until the first side is nicely browned, about 3 to 4 minutes.
Flip the breasts and brown the second side for 3 to 4 minutes.
Add about 1/2 inch of water to the pan, cover with the lid, reduce heat to medium, and steam until an instant-read thermometer inserted into the thickest part reads 165°F, about 5 to 8 minutes (longer for large breasts); add more water if it evaporates.
Remove the pan from heat and let the chicken rest for 5 minutes.
Transfer the cooled breasts to a stand mixer fitted with the paddle attachment; start on low and increase to medium briefly, mixing until the chicken is mostly shredded but not puréed.
Finish pulling apart any larger pieces by hand, then use the shredded chicken as desired.
