Chop & mince your butternut squash, onion, garlic, and ginger, and then set aside.
Heat all your oil over medium heat for about 1 minute, then add the nigella, mustard, and fennel seeds and lower heat to low, cooking for 2-3 minutes, until the spices start to pop.
Add in your onion and cook for about 7 minutes, allowing the onion to cook down a bit and just start to brown.
Drop in the ground coriander and turmeric and stir well, cooking for 1 more minute.
Stir in the minced garlic and ginger and butternut squash, and then raise the heat to medium-low, cooking for about 2 minutes before adding the water. Cook for 15 more minutes, stirring occasionally.
Add in the chicken and cook with the lid on for 8-10 more minutes, until chicken is almost done, stirring occasionally.
Stir in the amchur, salt, and honey (if using), and let cook 1 more minute before turning off the heat and serving immediately.