Add the chicken breast and peppers into a large bowl.

Sprinkle with salt and pepper.

Juice two lemons into bowl and add in olive oil. Toss to combine.

Cover and let marinate in the fridge for at least 2 hours or overnight.

Grill chicken and peppers on medium high heat for 5 minutes each side or until the chicken reaches an internal temperature of at least 165 degrees Fahrenheit.

Chop and shred chicken and peppers and add on top of warm taco shells.

Top with diced onion and cilantro.