Cut the skinless, boneless chicken breasts into 2-inch cubes, ensuring uniform size for even cooking.

Combine sweet chili sauce, soy sauce, sesame oil, rice wine vinegar, salt, and pepper in a medium bowl to create the marinade.

Pour half of the marinade over the chicken pieces, toss to coat evenly, cover, and refrigerate for at least 30 minutes.

Chop the pineapple, red bell pepper, and onion into 2-inch chunks.

Assemble the kabobs by alternating marinated chicken pieces with chunks of pineapple, red bell pepper, and onion on metal skewers.

Preheat your grill to high heat, around 400°F (200°C).

Grill the kabobs for about 6 minutes per side or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C).

Simmer the remaining marinade in a small saucepan while kabobs are grilling.

Once the kabobs are done, drizzle the warmed sweet and sour sauce over each skewer before serving.