Prep the chicken: Trim any excess fat.
Pat the chicken dry with paper towels so the sauce clings better.
Make the sauce: In a bowl, whisk together honey, soy sauce, chicken broth, garlic, ginger, rice vinegar, sesame oil, and red pepper flakes if using.
Load the slow cooker: Place the chicken in the slow cooker in an even layer. Pour the sauce over the top, making sure the chicken is coated.
Cook low and slow: Cover and cook on Low for 3.5 to 4.5 hours (thighs) or Low for 2.5 to 3.5 hours (breasts), until the chicken is tender and reaches 165°F internally. Avoid overcooking breasts to keep them juicy.
Shred or slice: Transfer the chicken to a cutting board.
Shred with two forks or slice into chunks. Tent with foil to keep warm.
Thicken the sauce: Turn the slow cooker to High. In a small bowl, stir cornstarch with cold water to make a slurry.
Whisk the slurry into the sauce and cook uncovered for 10 to 15 minutes until glossy and slightly thickened.
Bring it together: Return the chicken to the slow cooker and toss in the sauce until fully coated. Taste and adjust seasoning—add a splash of vinegar for brightness or more honey for sweetness.
Serve: Spoon chicken and sauce over hot rice. Garnish with green onions and sesame seeds.
Add steamed veggies on the side for a complete meal.