Heat olive oil in a large nonstick skillet over MEDIUM-HIGH heat. Add the chicken and season with salt, garlic, and pepper. Cook, stirring occasionally, until well browned, for about 6 to 8 minutes. Transfer the chicken to a large bowl. Then, add the about a teaspoons of oil to the same pan and return it to the heat. Add the zucchini, bell pepper and garlic and cook, stirring occasionally, until the vegetables are just barely fork tender, for about 5 minutes. Transfer the zucchini mixture to the large bowl with the chicken and set aside.