In a large bowl, whisk together the yogurt, lime juice, tamarind paste (or brown sugar + lemon juice), garam masala, cumin, hot sauce, and sugar until smooth.
Add water a little at a time until the sauce is pourable but still creamy.
Place the potato chips on a large serving platter or divide among individual plates.
Evenly scatter the garbanzo beans, jalapeño, bell pepper, red onion, and green onion over the chips.