In a blender jar, mix the almonds, onion, tomato, serrano, garlic, ginger, turmeric, salt, garam masala, cumin, coriander, cayenne, and water. Blend into a smooth purée. Pour the sauce into the inner cooking pot of the Instant Pot. Place the chicken on top. If the chicken is frozen, push it down into the sauce a little. Lock the lid into place. Select Manual and adjust the pressure to High. Cook for 10 minutes. When the cooking is complete, let the pressure release naturally. Unlock and remove the lid. Carefully remove the chicken to a board and cut it into bite-size pieces. Stir the coconut milk, garam masala, and tomato paste into the pot. Return the chicken to the pot, and garnish with the slivered almonds and cilantro. Pour the saffron milk along with the saffron strands over the rice and serve.