First, dice the chicken to 2-inch cubes.
Second, rinse and chop the cilantro, mint and serrano peppers. Next grind the cilantro leaves, mint leaves, serrano peppers, cumin seeds, lemon juice with 2 tablespoons of water in a blender.
In a separate large bowl, mix Greek yogurt with ginger garlic paste, garam masala, dried fenugreek leaves, salt, and 1.5 tablespoons oil.
Add in the ground green mix to the Greek yogurt marinade. Mix well. Furthermore, add in the diced chicken.
Cover with a lid and let it marinate for a minimum of 30 minutes in the refrigerator. Ideally 6 hours is perfect. But if you are in a time crunch 30 minutes is good.