Mix olive oil, lemon juice, garlic, and Moroccan seasoning together in a medium bowl.
Cut chicken into bite size pieces, add to bowl, stir to cover and refrigerate for minimum 30 minutes but up to about 8 hours.
Slice onion and pepper into thick slices. You can do this right before grilling or hours ahead of time and refrigerate until ready to use.
Alternate chicken with veggies on skewers, pour remaining marinade over kebabs.
Grease grill, or use grill mats, with a high temperature oil and turn on to a medium-high heat.
Grill kebabs for about 15 minutes, turning every few minutes so each side is evenly cooked.
Remove from grill, and use caution when removing if using metal skewers. Serve with rice or salad of your choice.