Place chicken breasts cubes in a glass bowl or large resealable plastic bag. Add lemon juice, zest, grated garlic, salt and pepper to the chicken toss until chicken is evenly coated with marinade. Refrigerate for 20 minutes or up to overnight.
Heat pan over medium-high heat. Add chicken to the pan along with all of the marinade. Sauté chicken, stirring frequently, until lightly browned, about 5-7 minutes. Alternatively, you can prepare the chicken in the oven.