Coat a slow cooker with cooking spray. Place the bell pepper strips and pork chops into the slow cooker. Pour the teriyaki sauce, vinegar, red pepper flakes, and garlic over the pork chops.
Cover and cook on low until the pork is very tender, 8 to 9 hours. Once tender, remove the pork from the slow cooker, and whisk in the peanut butter until smooth. Use a fork to shred pork. Return the pork to the slow cooker, and cook 10 minutes more.
Pour into a serving dish and sprinkle with peanuts to garnish (optional).