Spray the inside of a 6 quart slow cooker with cooking spray. Arrange the chopped vegetables on the bottom of the slow cooker.
Arrange the chicken and pineapple chunks on top. Whisk together the sauce ingredients. Pour on top of the chicken and pineapple.
Cook on low for 5 hours or until the chicken is fork tender and cooked through. Increase the slow cooker to the high setting.
Dissolve the cornstarch in cold water. Whisk into the sauce until thickened.
Simmer on high for 10-15 additional minutes.
Serve over rice.