To poach the chicken breasts, add the chicken to a Dutch oven or stock pot and fill with water until the chicken is 1" below the surface.
Bring the chicken to a boil then reduce to a simmer and cook for 15 minutes. Turn off the heat and let the chicken sit in the water for 7 more minutes. Drain the chicken and let it cool.
Once the chicken has cooled enough to handle it, dice the chicken and toss it into a large bowl.
Add the rest of the ingredients and toss to coat.
Place bowl into the refrigerator for at least 2 hours before serving.
Recipe by My Man's Belly at https://mymansbelly.com/2017/07/11/tarragon-chicken-salad/