In Instant pot add potatoes, water, and salt. Cook them on MANUAL for 8 Minutes. Quick-release. Peel the potato and slice them.
Begin by making green chutney. Transfer it to a bowl and keep it aside.
Masala mix: In a bowl, add 1/4 tsp each, ground cumin, Chaat masala, ground coriander, Ground black pepper, and salt for taste.
Spread the butter on each slice of bread than a generous amount of green chutney on each slice.
Layer with boiled potato, then sprinkle the masala powder on top. Repeat the process with green pepper and onion slices and cheese.
Top with another slice of bread and spread some butter on the top. Apply little butter on a panini maker or sandwich maker before placing the sandwich and grill it until golden color.
Cut it in the halve and serve it hot with ketchup.