Get a good fire going, aiming for a medium-high heat. You can cook your chicken pineapple kebabs on a camp stove, over hot coals, or even over the open flame of a fire pit.
Cut the pineapple into 1" chunks. Seed the peppers; cut the peppers and onion into roughly 1" squares.
Use a slotted spoon to remove chicken from the marinade; transfer remaining marinade to a small bowl or measuring cup to use as a baste.
Thread the prepared ingredients onto your skewers, alternating a piece of chicken, with a piece of pineapple, a piece of onion, and a piece of pepper.
Spray the grill grate with grill spray, then arrange the skewers in a single layer, leaving some room between each skewer. Cook for about 4-6 minutes, until chicken sears on one side. Flip the skewers, brush the top side of each skewer with a bit of marinade, and continue cooking until chicken reaches an internal temperature of 160 degrees F when an instant-read thermometer is inserted.
Flip the skewers, brush with some of the reserved marinade, and continue cooking until chicken reaches an internal temperature of 165 degrees F when an instant-read thermometer is inserted.
Flip one last time and sear for just a minute or so, then remove from heat. Serve hot, with a side salad or coconut rice.