In a bowl, whisk together olive oil, lemon juice, minced garlic, salt, and pepper to create the marinade.
Add the chicken cubes to the marinade, tossing to coat evenly. Cover and refrigerate for at least 2 hours, preferably overnight for maximum flavor.
While the chicken marinates, prepare the vegetables by cutting bell peppers, red onion, and zucchini into 1-inch pieces or rounds.
Preheat your grill to a medium-high heat until it feels hot and slightly smoky when hovered over with your hand.
Thread the marinated chicken, bell peppers, onion, and zucchini onto the soaked skewers, alternating ingredients for a colorful display.
Place the skewers on the grill, hearing the sizzle as they make contact with the hot grates. Close the lid and cook for about 10-12 minutes, turning occasionally.
Watch for charring on the edges of the vegetables and chicken, and listen for the bubbling juices and crackling sounds that indicate that the meat is cooking thoroughly.
Check the chicken for doneness by piercing a piece; it should be firm, with clear juices running out, and no pink inside.
Remove the skewers from the grill and let them rest for a couple of minutes. Sprinkle with chopped herbs for fresh flavor and presentation.
Serve the grilled kabobs hot, with a side of your favorite dip or salad, enjoying the smoky aroma and vibrant colors.