Heat The Olive Oil In A Large Skillet Over Medium-High Heat. Place The Chicken Breasts In The Hot Oil And Cook Until Browned On One Side, About 3 Minutes. Flip The Chicken And Add The Onions; Cook Another 2 Minutes. Add The Tomatoes, Garlic Salt, And Water To The Chicken; Stir. Season With 1 1/2 Teaspoon Garam Masala. Bring The Mixture To A Boil. Reduce Heat To Medium-Low, Cover, And Simmer Another 10 Minutes, Stirring Occasionally. Stir The Remaining 1/2 Teaspoon Garam Masala Through The Mixture. Raise Heat To Medium And Bring Mixture To A Boil. Cook Until The Chicken No Longer Pink In The Center And The Juices Run Clear, About 5 Minutes More. An Instant-Read Thermometer Inserted Into The Center Should Read At Least 165 Degrees F (74 Degrees C).