Prep the chicken: Cut the boneless chicken into even, bite sized cubes. Wash well.
Mix the marinade: Combine curd, ginger garlic paste, paprika, black pepper, cumin powder, turmeric powder, olive oil, lemon juice, and salt in a large bowl.
Marinate: Add the chicken to the marinade, toss to coat, and refrigerate for 3 to 4 hours.
Cut the vegetables: Cut the onion, bell peppers, and tomato into bite sized pieces.
Thread the skewers: Alternate chicken and vegetables onto the skewers.
Grill: Cook over medium-high charcoal heat for 12 to 15 minutes, turning occasionally.
Baste: Brush with melted butter while grilling to keep the chicken juicy.
Serve: Remove once the chicken is fully cooked and vegetables are lightly charred.