Creating the Simple Chicken Breast with Onions and Tomatoes is straightforward if you follow these steps:

1. Prepare the Ingredients: Begin by slicing the onions and dicing the tomatoes. Set these ingredients aside to have them ready when needed.
2. Heat Oil: In a large skillet, heat the olive oil over medium heat. It will take about 1 minute to warm up.
3. Cook Chicken: Season the chicken breasts with garlic powder, oregano, salt, and pepper. Add them to the skillet and cook for about 5 minutes on each side, or until browned and cooked through. This should yield a nice golden crust on the chicken.
4. Add Onions and Tomatoes: Once the chicken is cooked through, add the sliced onions and diced tomatoes to the skillet. Stir everything together and let it cook for an additional 10 minutes. The onions should become soft and translucent, while the tomatoes release their juices.
5. Garnish and Serve: Once everything is thoroughly cooked, remove from heat. You can garnish it with fresh basil if desired. Serve hot.

This simple process allows you to create an incredible meal without excessive effort.