First, cook and cool the chicken:
On the stove, in a saucepan add chicken and cover by 1 inch with chicken stock or broth. Add Rotisserie Chicken Seasoning if using. Bring to a good simmer, then turn down the heat and continue to cook at a bare simmer until chicken has cooked through about 12 minutes. If time allows, cool in the stock, then drain. Stock may be reserved for another use.
To use the Instant Pot, add chicken, Rotisserie Chicken Seasoning if using, and stock to cover by 1 inch. Seal and set to High Pressure, 10 minutes. Allow a 20-minute natural release then vent any remaining pressure. If time allows, remove liner from pot and continue to let chicken cool. Stock may be reserved for another use.
For both methods:
Shred chicken, preferably with a mixer, either a stand mixer or hand mixer. A food processor with a dough or cutting blade works well, too, in batches. Place mayonnaise in a large bowl, add the lemon juice, salt and/or seasoning salt, pepper and parsley. Mix together. Add chicken in two or three batches, mixing after each. Taste and adjust seasonings and add more mayonnaise if desired .
Serve immediately if you wish; it’s better if placed in the fridge for an hour before serving. There are no stabilizers in this recipe; stir back together if at any point the dressing becomes watery during storage.