In a bowl, mix the chicken pieces with pickling spice mix, ginger-garlic paste, red chili powder, cumin powder, coriander powder, turmeric powder, yogurt, and salt.
Let it marinate for 30 minutes.
Heat oil in a pan and add mustard seeds, fennel seeds, fenugreek seeds, nigella seeds, and cumin seeds.
Saute until fragrant.
Add onions and saute until golden brown.
Add tomatoes and cook until the mixture turns into a thick paste.
Add the marinated chicken and saute for a few minutes.
Add 1 cup of water and simmer until the chicken is cooked through.
Sprinkle red chili flakes and coriander leaves on top and serve hot with rice or naan. Enjoy!