Boil chicken breast until cooked through, then shred into fine pieces using two forks.
Blend chopped tomatoes, half the onion, garlic paste, paprika, cumin powder, and salt into a smooth sauce.
Heat olive oil in a skillet, sauté remaining sliced onions until soft.
Pour blended sauce and water into the skillet; simmer for 8 minutes until thickened.
Stir in shredded chicken, coat well, and spoon inside warm tortillas garnished with coriander.