Pour water into the Instant Pot. Place trivet in the pot. Place the chicken on top of the trivet. Sprinkle the chicken with the seasoned salt.
Cover the pot and secure the lid. Make sure valve is set to sealing. Set the manual/pressure cook button to 15 minutes (thawed chicken) or 20 minutes (frozen chicken). When the time is up let the pot sit for 10 minutes and then move the valve to venting.
In a bowl stir together the mustard, honey, mayonnaise and pepper. Use tongs to place the chicken into the bowl. Shred up the chicken and coat it with the sauce. Salt to taste.
Serve chicken hot or cold on top of buns with sliced pickles.