To a bowl, add the pineapple juice, sriracha, soy sauce, hoisin sauce, brown sugar, garlic, salt, pepper, garlic powder, and pineapple chunks. Mix until combined.
Add chicken and bell peppers to the slow cooker. Add the sauce on top.
Cook on LOW for 7 to 8 hours, or HIGH for 3 to 4 hours.
Remove the chicken breasts and shred before adding the shredded chicken back into the slow cooker.
In a small bowl, make a cornstarch slurry with 1 tbsp cornstarch and 1 tbsp water. Add the cornstarch slurry to the slow cooker and cook for another 30 minutes until the sauce has thickened to your liking.
Served with rice, green onions, and sesame seeds.