Add chicken, bell peppers, and pineapple to a slow cooker.
In a medium bowl whisk together garlic, red pepper flakes, sugar, 1 cup
water, and sweet red chili sauce. Pour this sauce into slow cooker and stir to combine. Cover and cook on high 2-3 hours or on low 4-5 hours.
About 30 minutes before serving, take the lid off the slow cooker. In a
small bowl stir together cold water and corn starch. Set the slow cooker on
high and pour the slurry of water and corn starch into the pot. Stir, then cover
and cook another 30 minutes.