Arrange chicken breasts on the bottom of the slow cooker.
Whisk together honey, tamari, blackberry jam, hoisin, olive oil, garlic, onions, and red pepper flakes. Pour mixture over chicken. Cover and cook on low 4-5 hours.
Using forks shred the chicken and set aside.
Mix cornstarch with 1.5 tsp water to make a slurry.
Pour remaining liquid from slow cooker into a saucepan. Over medium-high heat the liquid and add the cornstarch slurry, whisking constantly. Cook about 3 minutes to thicken. Pour sauce over chicken and mix together.
Top with chopped green onions. Serve over rice or other starch.