Add the chicken thighs to the bottom of a slow cooker.
In a separate bowl, whisk together the brown sugar, soy sauce, bourbon, apple cider vinegar, ground ginger, honey, red pepper flakes, and minced garlic.
Pour the sauce mixture over the chicken in the slow cooker.
Cover and cook on high for 4 hours or low for 6 hours, until the chicken is cooked through and tender.
Remove the chicken from the slow cooker and chop or shred it to your preferred texture.
In a small bowl, mix the cornstarch and water to make a slurry. Stir it into the sauce in the slow cooker.
Return the chopped chicken to the slow cooker and stir everything together. Let cook for another 5–10 minutes until the sauce thickens.
Turn off the heat and garnish with chopped green onions before serving.
Serve over white rice, brown rice, or cauliflower rice for a low-carb option.