Place chicken breasts in the slow cooker in a single layer.

In a bowl, mix pineapple juice, brown sugar, soy sauce, crushed pineapple, minced garlic, ground ginger, salt, and pepper.

Pour the sauce over the chicken breasts in the slow cooker and shake to coat.

Cook on low for 6–7 hours or high for 3–4 hours until internal temperature reaches 165°F.

Remove chicken and whisk together cornstarch and water in a small bowl until smooth.

Stir the cornstarch slurry into the cooking liquid and cook on high for 10–15 minutes until thickened.

Return chicken to the slow cooker and stir in the sauce for another 10–15 minutes.

Serve over rice or noodles, garnished with green onions and sesame seeds if desired.