Place the boneless skinless thighs at the bottom of the slow cooker.

Add the chopped red bell pepper, yellow bell pepper, and drained pineapple chunks, keeping the juice set aside.

In a small bowl, whisk together the reserved pineapple juice, soy sauce, brown sugar, and minced garlic.

Pour the sauce mixture over the meat and vegetables in the slow cooker.

Cover and cook on low for 6 hours or high for 3 hours until the meat is tender and fully cooked.