Add all ingredients to the slow cooker. Stir to mix well.
Cook HIGH 2-4 or LOW 4-6 hours.
Instant Pot
Turn the Instant Pot to saute, LOW temperature. Once hot, add the oil, onion, and garlic. Cook a few minutes, stirring frequently. Stir in the garam masala, paprika, salt, ginger, and pepper. Saute 1 minutes.
Stir in the diced tomatoes. Deglaze the bottom by of the pressure cooker by scraping and bits off with a wooden spoon. Stir in tomato paste and chicken.
Close lid and seal valve. Set high pressure and cook 9 minutes. Quick release pressure.