Season pork loin. Sauté in the instant-pot until all sides are brown. Cook on the meat setting for recommended time, (usually one hour).
Slice the loaf of bread down the middle horizontally so that you have two pieces. Then cut the bread into the desired individual sandwich size pieces.
Once the pork loin is done, shred it using two forks, or using a knife, roughly chop the meat. NOTE: Half of the pork loin can be reserved for another recipe if desired.
Slather the mustard on one side of the loaf to evenly cover it. Begin layering with the ham, pork loin, cheese, and pickles.
Grill the sandwich using a sandwich press, or grill it in a skillet and weigh it down with another skillet or something moderately heavy on top of it. Grill 5 minutes per side if using a skillet.
Sandwich is done when cheese is melted and both sides are brown.