Combine cubed chicken, peppers, and onion in a bowl.
Season with the seasoned salt, garlic and ginger powders.
Place mixture into the slow cooker and add ¼ C of water. Cook on high for 1.5 hours or low for 3-4, stirring occasionally to mix flavors and prevent sticking.
After cooking time is reached, add the pineapple and bottle of teriyaki sauce. Mix well and continue to cook for another 1 hour on high or 3 hours on low
After cooking time is reached, with a slotted spoon, separate the sauce from the chicken, pineapple and peppers. Pour the sauce into a saucepan and add the reserved pineapple juice. Bring to a boil.
In a small bowl, combine the cornstarch and 2 tbsp. of water and mix well. Add to the boiling sauce, one tablespoon at a time and mix well. Sauce will begin to thicken.
When sauce is thickened, add it back to the slow cooker along with the chicken mixture.