In a large stock pot place chicken breasts so that they all fit comfortably/loosely in the pot and fill with water until there is about an inch of water above where they sit. Add all tried herbs and 1 tablespoons salt to the water.
Place pot on the stove.
After bringing the liquid to a boil, reduce heat to a bare simmer so that only an occasional bubble breaks the surface. At this point, partly cover the pot, cook for about 10 minutes, then turn off the heat, leaving the chicken to finish cooking in the hot water for 10-15 more minutes.
Remove chicken from water and place on cutting board to cool.
In a large container mix mayo, grapes, celery, walnuts, salt and pepper (to taste).
When chicken has cooled to the touch chop into bite sized pieces and mix in with mayo mixture.
Taste to adjust salt content. Cover and then refrigerate overnight or until cool (the flavors get better over night, but would work for immediate use).