Follow these straightforward steps to create Chicken Madras Curry:

1. Heat Oil: In a large pot or skillet, heat the vegetable oil over medium heat.
2. Sauté Onions: Add the chopped onions and cook until they become soft and translucent, about 5-7 minutes.
3. Add Garlic and Ginger: Stir in the minced garlic and grated ginger, cooking for another 1-2 minutes until fragrant.
4. Mix Spices: Add the Madras curry powder, cumin, coriander, turmeric, and green chilies. Stir well and let the spices cook for about 1 minute.
5. Add Chicken: Increase the heat and add the chicken pieces. Stir until they are well coated with the spice mixture and cook until browned, about 5-6 minutes.
6. Add Tomatoes and Coconut Milk: Pour in the diced tomatoes and coconut milk. Mix everything well and bring to a simmer.
7. Simmer: Reduce the heat, cover the pot, and let the curry simmer for about 20-25 minutes, stirring occasionally until the chicken is cooked through and tender.
8. Season to Taste: Check the seasoning and add salt to taste. Adjust spice levels according to your preference.
9. Garnish: Once cooked, remove from heat and garnish with fresh cilantro.

These steps will guide you to create a rich and aromatic Chicken Madras Curry that is sure to impress.