Sear the Chicken (Optional): Heat olive oil in a skillet over medium heat. Season the chicken breasts with salt and pepper, then sear each side for about 2-3 minutes until golden brown. Once seared, transfer the chicken to the Crock Pot.
Make the Sauce: In a medium bowl, combine soy sauce, brown sugar, bourbon, apple cider vinegar, ketchup, garlic powder, ground ginger, onion powder, and red pepper flakes (if using). Stir until the sugar dissolves and the mixture is well-combined.
Add the Sauce to the Crock Pot: Pour the sauce mixture over the chicken in the Crock Pot. Cover and cook on low for 4-6 hours or on high for 2-3 hours. The chicken should be fully cooked and tender.
Thicken the Sauce: Once the chicken is cooked, remove it from the Crock Pot and set it aside. In a small bowl, whisk together the cornstarch and water until smooth. Add the mixture to the sauce in the Crock Pot and stir to combine. Cover and cook on high for an additional 10-15 minutes, or until the sauce has thickened.
Shred the Chicken: After the sauce has thickened, shred the chicken using two forks and return it to the Crock Pot. Stir to coat the chicken in the sauce.
Serve: Serve the bourbon chicken over steamed rice or noodles. Garnish with chopped green onions and sesame seeds, if desired. Enjoy!